ST314A is the Hydrogen (H2) Leak detector which can used on any sealed device for leak detection. ST314A can detect 5% Hydrogen (H2) + 95% Nitrogen (N2), H2, CO, Methane(CH4), Ethanol(Natural gas) and with an extremely sensitive semiconductor sensor, it can detect small leakage down to 1PPM precisely. Also, the adjustable sensitivity level function makes the smallest leak point easy to find. And, with LCD display and front illumination by a LED tip light, these intelligent designs give the professional engineer intuitive visual and auditory signal feedback for all common H2 leak detections.