This First Alert Hardwired Smoke and Carbon Monoxide Detector includes a 10-year battery backup that continues to protect you in the event of a power failure. The alarm features electrochemical CO sensing technology, an ionization smoke detector, and an 85-decibel alarm. One button silences any nuisance alarms and tests detector functions, while lights indicate if the alarm detects smoke or carbon monoxide. The latching alarm indicator automatically identifies which unit initiated the alarm, even after conditions that set off the alarm have subsided. And an end-of-life signal enhances your safety by letting you know when it's time to replace the unit. Connect it to up to 12 compatible BRK or First Alert alarms within a single-family residence. Gender: unisex.