Hardwired 3-in-1 LED Strobe and Combination Smoke and Carbon Monoxide Detector with 10-Year Battery Back UpThe Kidde P4010ACLEDSCO 2 is an integrated 120 Volt AC wire in smoke and carbon monoxide (CO) alarm with 10 year sealed battery backup and LED strobe light that provides temporal patterns, visual and voice warnings. If smoke is detected, the P4010ACLEDSCO 2 will produce a steady flash warning (once per second) and sound 3 long beeps, followed by Fire, repeating. During a CO incident the strobe horn will sound four (4) short beeps, followed by Warning.