Relay Wire-In, Includes (1) Set of Form C Contacts, Power Source Hardwired, Product Type Smart Relay, For Use With BRK and First Alert Smoke, Heat and Carbon Monoxide Alarms, Manufacturer Warranty Length 10 yr Limited, Maximum Operating Temperature 100 Degrees F, Minimum Operating Temperature 40 Degrees F, Operating Voltage 120V AC, Overall Height 1 in, Overall Length 3.5 in, Overall Width 1.5 in, Standards UL 2034, UL 217, UL 539