BW Technologies Yellow Gas Alert Extreme Portable Single Gas Monitor is used for surveying levels of hydrogen sulfide in natural and industrial environments. It features continuous LCD for real time gas concentrations and tamper proof settings with pass code protection. Detector is equipped with 95 dB tone and bright LED indication internal vibrating alarm for high noise areas. Calibration is a simple automatic procedure and compatible with BW? MicroDock II automatic test and calibration system. It includes stainless steel alligator Clip test cap and hose, battery, multi language CD manual. Detectors with easy on/off operation has long lasting durability and ideal to use in personal safety, training, research and ambient air monitoring applications.