Powerful, portable, affordable, the BOLO® Professional Gas Leak Detector is a precision, microprocessor-controlled instrument designed to be used by service and safety professionals, for quick and easy detection of combustible gas leaks. Detects very low levels of propane, methane, butane, etc. Comes as complete kit, with hard case, detector, earphone, batteries, soft pouch.NOVA Systems Products, www.nsl1.com, (866) 734-0200.