The Tracerline PRO-Chek CG Combustible Gas Leak Detector, No. TP-9363, can find leaks in CNG vehicles, acetylene welding tanks, propane tanks and more. It also detects gasoline, methanol, ethanol, methane, ethane, butane and other dangerous gases. It has twice the sensitivity as competitive units and features a three-position switch with a sensitivity slide that helps pinpoint the location of each leak, according to the company. Additional features include a variable-intensity auto alarm and flashing yellow LED to determine the size of the leak, and an auto-zero function that blocks out background gas levels.