Width -, digital readout no, battery backup yeshush button yes, locking pin yes, operating temp. Photoelectric respond best to slow-smoldering fires. All interconnect units must interface directly with their own brand of interconnectable smoke and co alarms. 1xth3 and 5mpl0 feature voice that announces fire, carbon monoxide, and low battery warnings when detected. 2ftp5 includes voice warning with location of danger detected, and has 2 latching features: 1 identifies initiating alarms and the other low battery. Combination smoke/co alarmscan silence nuisance and low-battery alarms. Test/reset button function test11s alarm circuitry, alarm activation, and peak level memory. Feature green led power-on indicator. Visual red led indicates when alarm is activated. 85db horn. Easy installation. Operating temp: 40 to 100 f. 120vac, 60 hz. Meet nfpa 72 standards.