The MEL REM ATDD has the AC/DC EMF measurement and ambient temperature measuremnent functions as all MEL Meters. It also adds REM and ATDD functions. The antennta radiates a discrete EM field that will react to energy changes and alert you with sound alert and 6 LEDlights that light up in accordance to the strength and proximity of the disturbing source. ATDD function sets off a sound a led light alert in response to a drop or increase in temperature of 5 degrees F. The readout for regular Temperature and EMF levels has a red bacground light that one can turn off. It is nightvision friendly since it is red. There is a built in red led light that one uses as nightvision friendly flashlight. This quality product has a 1 year manufacturer's warranty.