Combustible Gas Detector with CaseUnit is preset at normal sensitivity, but you can switch to high or low. Slow beeping indicates that unit is warmed up. Frequency increases when a leak is detected until an alarm sounds when moving into high gas concentration. The SmartAlarm LED indicates leak size.If no leak is detected in a suspected area, select high sensitivity. This will detect even low levels in the area. Move the tip over more defined areas, and you will be alerted when the tip encounters the concentration at the leak source.With ultra - sensitive, long life sensor. Detects all hydrocarbon and other combustible gases including propane, methane, butane, industrial solvents and more.Unit is preset at normal sensitivity, but you can switch to high or low. Slow beeping indicates that unit is warmed up. Frequency increases when a leak is detected until an alarm sounds when moving into high gas concentration. The illuminated bar graph indicates leak size.If no leak is detected in a suspected area, select high sensitivity. This will detect even low levels in the area. Move the tip over more defined areas, and you will be alerted when the tip encounters the concentration at the leak source.Ultra - sensitive sensor detects less than 15 ppm methane and better than 12 ppm for propane. Performs equally well on a complete list of detectable gases including acetylene, butane, and isobutaneAutomatic calibration and zeroingSensor replacable after full service lifeSmartAlarm LED shows how big or small a leak is on a scale of 1 to 924 - month limited warranty (12 - month warranty on sensor)Made in the USA.