Therma-Hygrometer, 6100 model with an interchangeable probe. Ranges -20 to +70 C and 0 to 100%RH. The unit incorporates a clear custom backlit LCD display that simultaneously shows both temperature and humidity readings. The units require 3 standard AAA batteries and have a minimum life of 10,000 hours, with an auto power off facility to maximise the battery life. The interchangeable probe can be easily replaced and comes with a 1M cable and a 6-pin Lumberg connector.