Model Number Description Your Price Purchase
41BP-10000101 Banana Plug 3.8 N/A

Discontinued

41BP-10000301 Banana Plug 4 N/A

Discontinued

63BH-0B100101 Banana Holder N/A

Discontinued

63BP-0B1003A1 Banana Plug Shell N/A

Discontinued

63BP-AB100101 Banana Plug Shell N/A

Discontinued

ADB-002 DC Block BNC 50 [GSP-9330/GSP-9300B]
$63.70
$70.00
$70.00
Add to Cart Request Quote
ADB-006 DC Block N-type 50 [GSP-9330/GSP-9300B]
$63.70
$70.00
$70.00
Add to Cart Request Quote
ADB-008 DC Block SMA-type 50 [GSP-9330/GSP-9300B]
$39.13
$43.00
$43.00
Add to Cart Request Quote
ADP-001 Adaptor (BNC-N) [GSP-Series]
$37.31
$41.00
$41.00
Add to Cart Request Quote
ADP-002 Adaptor (SMA-N) [GSP-Series]
$50.96
$56.00
$56.00
Add to Cart Request Quote
ADP-003 50 N-Type female to SMA female Adapter [USG-Series] N/A

Discontinued

ADP-101 Adapter (BNC-BNC) [GSP-Series]
$172.90
$190.00
$190.00
Add to Cart Request Quote
AEL-5002-350-18.75 AC/DC Electronic Load (1875/3750W; 50~350Vrms/500Vdc) Request Quote
AEL-5002-425-18.75 AC/DC High Power Electronic Load (1875/3750W; 50~425Vrms/600Vdc) Request Quote
AEL-5003-350-28 AC/DC High Power Electronic Load (2800/5600W; 50~350Vrms/500Vdc) Request Quote
AEL-5003-425-28 AC/DC High Power Electronic Load (2800/5600W; 50~425Vrms/600Vdc) Request Quote
AEL-5003-480-18.75 AC/DC High Power Electronic Load (2800/5600W; 50~480Vrms/700Vdc) Request Quote
AEL-5004-350-37.5 AC/DC High Power Electronic Load (3750/7500W; 50~350Vrms/500Vdc) Request Quote
AEL-5004-425-37.5 AC/DC High Power Electronic Load (3750/7500W; 50~425Vrms/600Vdc) Request Quote
AEL-5004-480-28 AC/DC High Power Electronic Load (3750/7500W; 50~480Vrms/700Vdc) Request Quote
AEL-5006-350-56 AC/DC High Power Electronic Load (5600/11200W; 50~350Vrms/500Vdc) Request Quote
AEL-5006-425-56 AC/DC High Power Electronic Load (5600/11200W; 50~425Vrms/600Vdc) Request Quote
AEL-5008-350-75 AC/DC High Power Electronic Load (7500/15000W; 50~350Vrms/500Vdc) Request Quote
AEL-5008-425-75 AC/DC High Power Electronic Load (7500/15000W; 50~425Vrms/600Vdc) Request Quote
AEL-5012-350-112.5 AC/DC High Power Electronic Load (11250/22500W; 50~350Vrms/500Vdc) Request Quote
AEL-5012-425-112.5 AC/DC High Power Electronic Load (11250/22500W; 50~425Vrms/600Vdc) Request Quote
AEL-5015-350-112.5 AC/DC High Power Electronic Load (15000/30000W; 50~350Vrms/500Vdc) Request Quote
AEL-5015-425-112.5 AC/DC High Power Electronic Load (15000/30000W; 50~425Vrms/600Vdc) Request Quote
AEL-5019-350-112.5 AC/DC High Power Electronic Load (18750/37500W; 50~350Vrms/500Vdc) Request Quote
AEL-5019-425-112.5 AC/DC High Power Electronic Load (18750/37500W; 50~425Vrms/600Vdc) Request Quote
AEL-5023-350-112.5 AC/DC High Power Electronic Load (22500/45000W; 50~350Vrms/500Vdc) Request Quote
AEL-5023-425-112.5 AC/DC High Power Electronic Load (22500/45000W; 50~425Vrms/600Vdc) Request Quote
AFG-125 Instek AFG-125 25 MHz USB Modular Arbitrary Function Generator, Single Channel N/A

Discontinued

AFG-125P Instek AFG-125P 25 MHz USB Modular Arbitrary Function Generator with Power Supply, Single Channel N/A

Discontinued

AFG-2005 Instek AFG-2005 Arbitrary Function Generator 5MHz
$226.59
$236.55
$236.55
Add to Cart Request Quote
AFG-2005-OB 5MHz Arbitrary Function Generator ?This open box item may be missing original packaging, missing some small accessories or a lightly used demo unit. N/A

Discontinued

Replaced by: AFG-2005

AFG-2012 Instek AFG-2012 Arbitrary Function Generator 12MHz
$268.45
$295.00
$295.00
Add to Cart Request Quote
AFG-2025 Instek AFG-2025 Arbitrary Function Generator 25MHz
$321.23
$353.00
$353.00
Add to Cart Request Quote
AFG-2105 Instek AFG-2105 Arbitrary Function Generator 5MHz
$294.84
$324.00
$324.00
Add to Cart Request Quote
AFG-2112 Instek AFG-2112 Arbitrary Function Generator 12MHz
$313.95
$345.00
$345.00
Add to Cart Request Quote
AFG-2125 Instek AFG-2125 Arbitrary Function Generator 25MHz
$341.25
$356.25
$356.25
Add to Cart Request Quote
AFG-2225 2 Channel, 25MHz, w/Ext. counter, sweep, AM/FM/FSK
$335.79
$369.00
$369.00
Add to Cart Request Quote
AFG-225 Instek AFG-225 25 MHz USB Modular Arbitrary Function Generator, Dual Channel N/A

Discontinued

AFG-225P 25 MHz, 2CH USB Arbitrary Waveform Generator w/Power Supply N/A

Discontinued

AFG-3000 OPT.01 GPIB card for AFG-3021/22/31/32 [Field install]
$173.81
$191.00
$191.00
Add to Cart Request Quote
AFG-3021 20 MHz, Single Channel Arbitrary Function Generator
$1,347.10
$1,418.00
$1,418.00
Add to Cart Request Quote
AFG-3021-B Instek AFG-3021 20 MHz Single Channel Arbitrary Function Generator DEMO UNIT. FULL WARRANTY. Not all accessories or original packaging may be included N/A

Discontinued

Replaced by: AFG-3021

AFG-3022 20 MHz, Dual Channel Arbitrary Function Generator
$2,034.90
$2,142.00
$2,142.00
Add to Cart Request Quote
AFG-3031 30 MHz, Single Channel Arbitrary Function Generator
$1,456.35
$1,533.00
$1,533.00
Add to Cart Request Quote
AFG-3032 30 MHz, Dual Channel Arbitrary Function Generator
$2,254.35
$2,373.00
$2,373.00
Add to Cart Request Quote
AFG-3051 50MHZ Arbitrary Function Generator
$1,796.45
$1,891.00
$1,891.00
Add to Cart Request Quote
AFG-3081 80MHZ Arbitrary Function Generator
$2,693.25
$2,835.00
$2,835.00
Add to Cart Request Quote
APP-1001 LinkView Software for PS and e-LOAD/ Charge and Discharge Software
$1,130.50
$1,190.00
$1,190.00
Add to Cart Request Quote
APS-001 GPIB Interface Card for APS-7050/APS-7100
$238.42
$262.00
$262.00
Add to Cart Request Quote
APS-002 RS232 Interface card for APS-7050/APS-7100
$95.55
$99.75
$99.75
Add to Cart Request Quote
APS-003 Output Voltage Capacity: 0-600Vrms APS-7050/APS-7100
$286.65
$299.25
$299.25
Add to Cart Request Quote
APS-004 Output Frequency Capacity (45~999.9Hz)
$286.65
$315.00
$315.00
Add to Cart Request Quote
APS-008 Air Inlet Filter Compatible with ASR-3000 Power Supply Series
$10.01
$11.00
$11.00
Add to Cart Request Quote
APS-1102 750VA/1000VA OUTPUT; AC and AC DC N/A

Discontinued

Replaced by: ASR-2100

APS-1102A 750VA/1000VA OUTPUT; AC and AC DC Power Source [Replaces APS-1102] N/A

Discontinued

Replaced by: ASR-2100R

, ASR-2100

APS-7050 500VA OUTPUT; AC Power Source
$2,352.82
$2,476.65
$2,476.65
Add to Cart Request Quote
APS-7050E 500VA OUTPUT; AC Power Source [Economy version]
$1,564.03
$1,646.35
$1,646.35
Add to Cart Request Quote
APS-7100 1000VA OUTPUT; AC Power Source
$3,127.16
$3,291.75
$3,291.75
Add to Cart Request Quote
APS-7100E 1000VA OUTPUT; AC Power Source [Economy version]
$2,304.08
$2,425.35
$2,425.35
Add to Cart Request Quote
APS-9050 AC Power Source 500 watts N/A

Discontinued

APS-9100 AC Power Source 1000 watts N/A

Discontinued

APS-9102 AC Power Source, 1000VA N/A

Discontinued

APS-9301 AC Power Source, 300VA N/A

Discontinued

APS-9501 AC Power Source, 500VA N/A

Discontinued

ASR-002 External Three-Phase Control Unit
$1,762.25
$1,855.00
$1,855.00
Add to Cart Request Quote
ASR-002-OB External Three-Phase Control Unit-This open box item may be missing original packaging, missing some small accessories or a lightly used demo unit. N/A

Discontinued

Replaced by: ASR-002

ASR-003 GPIB Interface Card Opt. for ASR-6000
$357.63
$393.00
$393.00
Add to Cart Request Quote
ASR-004 Device Net Interface Card Opt. for ASR-6000
$298.48
$328.00
$328.00
Add to Cart Request Quote
ASR-005 CAN BUS Interface Card Opt. for ASR-6000
$238.42
$262.00
$262.00
Add to Cart Request Quote
ASR-006 External Parallel Cable Opt. for ASR-6000
$74.62
$82.00
$82.00
Add to Cart Request Quote
ASR-01 Air Inlet Filter
$9.10
$10.00
$10.00
Add to Cart Request Quote
ASR-2050 500VA Programmable AC/DC Source (USB+LAN)
$2,323.70
$2,446.00
$2,446.00
Add to Cart Request Quote
ASR-2050 GPIB 500VA Programmable AC/DC Source (GPIB+RS232/Factory Installed)
$2,568.80
$2,704.00
$2,704.00
Add to Cart Request Quote
ASR-2050R 500VA Programmable AC/DC Source for 3U 1/2 Rack Mount (USB LAN)
$2,225.85
$2,343.00
$2,343.00
Add to Cart Request Quote
ASR-2100 1000VA Programmable AC/DC Source (USB+LAN)
$3,149.25
$3,315.00
$3,315.00
Add to Cart Request Quote
ASR-2100 GPIB 1000VA Programmable AC/DC Source (GPIB+RS232/Factory Installed)
$3,394.35
$3,573.00
$3,573.00
Add to Cart Request Quote
ASR-2100R 1000 VA Programmable AC/DC Source for 3U 1/2 Rack Mount (USB+LAN)
$2,744.55
$2,889.00
$2,889.00
Add to Cart Request Quote
ASR-2100R-OB 1000 VA Programmable AC/DC Source for 3U 1/2 Rack Mount (USB+LAN) - This open box item may be missing original packaging, missing some small accessories or a lightly used demo unit. N/A

Discontinued

Replaced by: ASR-2100R

ASR-3200 2KVA Programmable AC/DC Source
$5,653.26
$5,950.80
$5,950.80
Add to Cart Request Quote
ASR-3300 3KVA Programmable AC/DC Source
$7,313.86
$7,698.80
$7,698.80
Add to Cart Request Quote
ASR-3400 4KVA Programmable AC/DC Source
$8,645.95
$9,101.00
$9,101.00
Add to Cart Request Quote
ASR-3400HF 4KVA Programmable AC/DC Source with 5000Hz output frequency
$10,260.00
$10,800.00
$10,800.00
Add to Cart Request Quote
ASR-6450 4.5kVA AC/DC Programming Source
$11,428.57
$12,000.00
$12,000.00
Add to Cart Request Quote
ASR-6600 6kVA AC/DC Programming Source
$15,238.10
$16,000.00
$16,000.00
Add to Cart Request Quote
ASR-GET-003 Extended Terminal for Universal Type (ASR-2000R only)
$129.22
$142.00
$142.00
Add to Cart Request Quote
ATA-001 BNC Antenna [GSP-Series]
$14.56
$16.00
$16.00
Add to Cart Request Quote
ATA-002 Near Field Probe N/A

Discontinued

ATN-100 10dB Attenuator, 50 Ohms, N(J/F)-N(P/M) Adaptor
$198.38
$218.00
$218.00
Add to Cart Request Quote
C-1200 Multi-Channel Lora Testers N/A

Discontinued

C-1201 I/O Extender with USB Cable Option for C-1200 Loop Test N/A

Discontinued

CGL-001 300MHz, 2GS/s, 4 Ch. with RS-232, USB, VPO Digital Oscilloscope. N/A

Discontinued

DAQ-900 20-Channel Universal Multiplexer (Solid State Relay)
$655.20
$720.00
$720.00
Add to Cart Request Quote
DAQ-901 20-Channel Universal Multiplexer (Solid State Relay)
$445.90
$490.00
$490.00
Add to Cart Request Quote
DAQ-903 40-Channel Single-Ended Multiplexer Module
$488.67
$537.00
$537.00
Add to Cart Request Quote
DAQ-904 4 x 8 Two-Wire Matrix Module
$488.67
$537.00
$537.00
Add to Cart Request Quote
DAQ-909 8+2 Channels High Voltage (DC 600V) High Current (2A) Multiplexer
$555.10
$610.00
$610.00
Add to Cart Request Quote
DAQ-9600 Data Acquisition System (Mainframe)
$1,653.00
$1,740.00
$1,740.00
Add to Cart Request Quote
DAQ-9600G Data Acquisition System (Mainframe) with GPIB
$2,071.00
$2,180.00
$2,180.00
Add to Cart Request Quote
DH2-FH1 Module Extension Bay + USB Cable for use with GDS-2000A Oscilloscope N/A

Discontinued

DS2-08LA 8-CHANNEL LOGIC ANALYZER MODULE [USE with GDS-2000A Series]
$544.18
$598.00
$598.00
Add to Cart Request Quote
DS2-16LA 16-CHANNEL LOGIC ANALYZER MODULE [USE with GDS-2000A Series]
$792.61
$871.00
$871.00
Add to Cart Request Quote
DS2-8LA 8-CHANNEL LOGIC ANALYZER MODULE [USE with GDS-2000A Series]
$544.18
$598.00
$598.00
Add to Cart Request Quote
DS2-FGN 5MHz DDS Function Generator module for GDS-2000A series
$232.96
$256.00
$256.00
Add to Cart Request Quote
DS2-FH1 Module Extension Bay for GDS-2000A Series N/A

Discontinued

DS2-FH1+A321 Module Extension Bay + USB Cable for use with GDS-2000A Oscilloscope N/A

Discontinued

DS2-GPIB GPIB Interface module for GDS-2000A series
$382.20
$420.00
$420.00
Add to Cart Request Quote
DS2-LAN Ethernet and SVGA Output module for GDS-2000A series
$268.45
$295.00
$295.00
Add to Cart Request Quote
DS3-PWR Instek DS3-PWR Power Analysis Software
$477.75
$525.00
$525.00
Add to Cart Request Quote
DS3-SBD Instek DS3-SBD Serial Bus Analysis Software
$477.75
$525.00
$525.00
Add to Cart Request Quote
EDUPackage1 Instek Educational Discount Package 1 - GDM-8034, GDS-1052-U And GFG-8216A N/A

Discontinued

EDUPackage2 Instek Educational Discount Package 2 - GDM-8145, GDS-1062A And GFG-8255A N/A

Discontinued

GAD-201G Automatic Distortion Meter N/A

Discontinued

GAG-809 Audio Generator, 10Hz - 1MHz N/A

Discontinued

GAG-810 Audio Generator, 1MHz N/A

Discontinued

GAG-810-b Audio Generator , 1MHz,
Missing original box and all accessories, including the power cord
N/A

Discontinued

GAK-001 Termination 50 ohm [GSP-Series]
$28.21
$31.00
$31.00
Add to Cart Request Quote
GAK-002 Adaptor, Cap with Chain, N(P/M)
$7.28
$8.00
$8.00
Add to Cart Request Quote
GAK-003 50 Ohm Impedance Adaptor
$69.16
$76.00
$76.00
Add to Cart Request Quote
GAM-101 Analog Multimeter N/A

Discontinued

GAP-001 AC/DC Adaptor for GDS-300/200 N/A

Discontinued

GAP-801 Preamplifier N/A

Discontinued

GAP-802 Preamplifier [GSP-830 only] N/A

Discontinued

GBK-002 GRF-1300A, Teacher Handbook
$50.05
$55.00
$55.00
Add to Cart Request Quote
GBM-01 4 Wire (Kelvin Clip) test lead, 90V(max.), approx:1100mm
$72.80
$80.00
$80.00
Add to Cart Request Quote
GBM-02 4 Wire(single pin) test probe, 80V(max.), approx. 1100mm
$228.41
$251.00
$251.00
Add to Cart Request Quote
GBM-03 4 Wire(twin pin) test probe, 300V(max.), approx. 1400mm
$254.80
$280.00
$280.00
Add to Cart Request Quote
GBM-03A 4 Wire (Twin Pin) Test probe, 1000V(Max), approx. 1400mm
$291.20
$320.00
$320.00
Add to Cart Request Quote
GBM-3080 80V Battery Meter with RS-232/USB Host/Device/Handler Interface
$2,048.58
$2,156.40
$2,156.40
Add to Cart Request Quote
GBM-3100H 1000V Battery Meter with RS-232C/USB and Handler Interface
$4,180.00
$4,400.00
$4,400.00
Add to Cart Request Quote
GBM-3300 300V Battery Meter with RS-232/USB Host/Device/Handler Interface
$2,732.20
$2,876.00
$2,876.00
Add to Cart Request Quote
GBM-S1 Short Bar for Instek GBM-02/GBM-03
$54.60
$60.00
$60.00
Add to Cart Request Quote
GBS-1074 70MHz, 4-channel Digital Oscilloscopes N/A

Discontinued

GBS-1104 100MHz, 4-channel Digital Oscilloscopes N/A

Discontinued

GBS-1204 200MHz, 4-channel Digital Oscilloscopes N/A

Discontinued

GCL-001 Vertical Calibration Cable for GDS-300/200 Series N/A

Discontinued

GCM-033 AC Current Clamp Meter. MAX. 600V/600A N/A

Discontinued

GCM-034 AC/DC Current Clamp Meter. MAX. 1000V/1000A N/A

Discontinued

Replaced by: 380976-K

GCM-302 Mini Clamp Meter 200A/600A N/A

Discontinued

GCM-303 Mini Clamp Meter 200A/600A with True RMS N/A

Discontinued

GCM-403 Digital Clamp Meter
$52.78
$58.00
$58.00
Add to Cart Request Quote
GCM-407 Digital Clamp Meter with True RMS Measurement
$66.43
$73.00
$73.00
Add to Cart Request Quote
GCP-005 Instek GCP-005 40Hz-1KHz/5A Current Probe GDS3000 N/A

Discontinued

GCP-020 Instek GCP-020 Current Probe, 40Hz-40kHz, 240A( 10mV/A) N/A

Discontinued

GCP-100 Instek GCP-100 DC-100KHz/10A Current Probe GDS3000 N/A

Discontinued

GCP-1000 DC~1MHz Current Probe/70A
$1,482.95
$1,561.00
$1,561.00
Add to Cart Request Quote
GCP-1030 100MHz/30A Current Probe
$5,416.90
$5,702.00
$5,702.00
Add to Cart Request Quote
GCP-201 Test Gripper for GLA N/A

Discontinued

GCP-206P Power Supply for Current Probe (2 Input Channel)
$980.40
$1,032.00
$1,032.00
Add to Cart Request Quote
GCP-210L for 20-50 MHz Osilloscope N/A

Discontinued

GCP-210LC for 20-50 MHz Osilloscope N/A

Discontinued

GCP-300 DC~300KHz Current Probe/200A
$716.17
$787.00
$787.00
Add to Cart Request Quote
GCP-425P Power Supply for Current Probe (4 Input Channel)
$1,462.05
$1,539.00
$1,539.00
Add to Cart Request Quote
GCP-500 DC~500KHz Current Probe/150A
$1,033.60
$1,088.00
$1,088.00
Add to Cart Request Quote
GCP-530 50MHz/30A Current Probe
$3,873.15
$4,077.00
$4,077.00
Add to Cart Request Quote
GCT-202 Option for GDM-201 Pen-Type Multimeter N/A

Discontinued

GCT-630 Ground Continuity Tester N/A

Discontinued

Replaced by: GPT-9904

GCT-9040 40A Ground Bond Tester
$1,713.80
$1,804.00
$1,804.00
Add to Cart Request Quote
GDB-02 oscilloscope education and training kit N/A

Discontinued

Replaced by: GDB-03

GDB-03 Instek GDB-03 Oscilloscope training kit for GDS3000
$261.17
$287.00
$287.00
Add to Cart Request Quote
GDM-01 Calibration Key for GDM-8261A/8255A
$6.37
$7.00
$7.00
Add to Cart Request Quote
GDM-201 Pen-Type Multimeter N/A

Discontinued

GDM-301 Digital Multimeter, Handheld N/A

Discontinued

Replaced by: GDM-350B

GDM-302 Digital Multimeter, Handheld N/A

Discontinued

Replaced by: GDM-350B

GDM-350A 3 1/2 digits N/A

Discontinued

Replaced by: GDM-350B

GDM-350B 3.5 Digit Handheld Multimeter [1,999 counts]
$22.75
$25.00
$25.00
Add to Cart Request Quote
GDM-351A 3.5 digit Hand Held N/A

Discontinued

GDM-352A Digital Multimeter, 3.5 digits, handheld N/A

Discontinued

GDM-354A 3.5 digit Hand Held N/A

Discontinued

GDM-356 3 1/2 digits N/A

Discontinued

Replaced by: GDM-541

GDM-357 3.5 Digit Handheld Multimeter [1,999 counts]
$47.32
$52.00
$52.00
Add to Cart Request Quote
GDM-360 Handheld DMM 6,000 Count w/RS232
$109.20
$120.00
$120.00
Add to Cart Request Quote
GDM-391A 3.75 digit hand-held Multimeter N/A

Discontinued

GDM-393A 3.75 digit Hand Held N/A

Discontinued

GDM-394 3 3/4 digits N/A

Discontinued

Replaced by: GDM-541

GDM-395 Handheld DMM 3 3/4 digits
$49.14
$54.00
$54.00
Add to Cart Request Quote
GDM-396 3 3/4 digits N/A

Discontinued

Replaced by: GDM-541

GDM-397 Handheld DMM 3 3/4 digits w/RS-232, MIN/MAX N/A

Discontinued

GDM-398 Handheld DMM 4 3/4 digits w/RS-232, MIN/MAX
$81.90
$90.00
$90.00
Add to Cart Request Quote
GDM-401 Digital Multimeter, Handheld N/A

Discontinued

GDM-450A 4.5 digit Hand Held N/A

Discontinued

Replaced by: GDM-452

GDM-451 4 1/2 digits N/A

Discontinued

Replaced by: GDM-452

GDM-452 Handheld DMM 4 1/2 digits
$86.45
$95.00
$95.00
Add to Cart Request Quote
GDM-461 Handheld DMM 22,000 Count Hand-held w/True RMS and RS-232C interface N/A

Discontinued

Replaced by: GDM-541

GDM-531 6000 Counts DMM
$26.39
$29.00
$29.00
Add to Cart Request Quote
GDM-532 9999 Counts DMM
$48.23
$53.00
$53.00
Add to Cart Request Quote
GDM-533 6000 Counts DMM(with USB Interface)
$91.00
$100.00
$100.00
Add to Cart Request Quote
GDM-541 22000 counts DMM(with USB Interface)
$109.20
$120.00
$120.00
Add to Cart Request Quote
GDM-8034 Bench DMM 3 1/2 digits N/A

Discontinued

Replaced by: GDM-8341

, GDM-8342

GDM-8040 Benchtop Digital Multimeter N/A

Discontinued

GDM-8041 LCD Digital Multimeter N/A

Discontinued

GDM-8055 5.5 digit Bench N/A

Discontinued

GDM-8135 3 1/2 digits N/A

Discontinued

Replaced by: GDM-8341

GDM-8145 4 1/2 digits N/A

Discontinued

Replaced by: GDM-8341

GDM-8245 50000 counts, dual display N/A

Discontinued

Replaced by: GDM-8341

GDM-8246 50000 counts, dual display w/RS-232 N/A

Discontinued

Replaced by: GDM-8341

X