This IR probe utilises a phototransistor with maximum response in the infrared region of the electromagnetic spectrum at around 940 nm. The phototransistor is mounted on the end of a fibreglass wand and fitted to 250mm flying leads with 4mm plugs. When connected to a suitable voltmeter or multimeter the probe will produce a qualitative reading proportional to the amount of infrared radiation incident on its sensitive face. Supplied with instructions. Requires connection to a multimeter or low voltage digital voltmeter, sensitive to at least 0.01V.