The DTM550 Model is a hand-held thermo-hygrometer developed by Tecpel. It is built with a temperature range of -20 ℃ to 100 ℃ and a humidity rate of 0% to 100% RH. This device has a backlight display and is capable to handle up to 3 1/2 digits. It is also supplied with automatic low battery indication and valox housing to withstand accidental drops.