The Dwyer 160S-36PM is a Permanent mount "S" type stainless steel Pitot tube that has a 36" insertion length. The Series 160S “S” Type Stainless Steel Pitot Tube is designed specifically for flow measurement of dirty, particulate-laden air or gas streams typical in a smoke stack and another environmental testing. Total and static pressure tubes are precisely aligned and welded together every 6 inches for maximum accuracy, strength, and long-term durability. Permanent mount (PM) models include a 1" welded stainless steel sleeve and adjustable compression fitting with 1" MNPT mounting threads.