A one-handed combustible gas sniffer that senses a broad range of flammable vapors and gases, from natural gas, propane and butane to gasoline, solvents and paint thinner, down to leak levels as small as a few parts per million. It uses a heated semiconductor sensor with a 15-inch gooseneck probe, warms up in about 10 seconds, reacts in under a second, and signals findings through a tri-color LED bar and buzzer, with user-adjustable high/low sensitivity and auto shut-off; this listing comes with a calibration certificate documenting traceable measurement accuracy.