Wired-in, 120 volt AC, 60Hz single or multiple station heat alarm. 9 volt battery backup. Microprocessor controlled, thermistor heat sensor, features fixed rate and rate of rise temperature sensing that allows unit to alarm prior to reaching the fixed temperature setting of 135 degrees F. IR remote control silence/test uses most remote controls to temporarily quiet unwanted alarms and test alarm functions. Two silence features can silence the low-battery chirp for up to eight hours or temporarily silence a nuisance alarm. UL Listed. 10-year limited warranty.