The Transforming Technologies GTS900 is a Deluxe combo tester and foot plate only, and this tests wrist straps and footwear (Left and Right Feet Independently) and has LEDs with audible sound indicating test results, that are battery powered. So, It's not location restricted with low battery signal test limits meets USA and European standards audible and visual alarms durable, solid metal construction factory calibrated and fixed ships with a calibration certificate.