This Universal Security Instruments USI/SM/HW10YR/P smoke detector provides comprehensive home safety with a hardwired power source and a 10-year sealed lithium-free alkaline battery backup. It features advanced Sensing Plus Multi-Criteria Detection with a photoelectric sensor to accurately identify both slow-smoldering and fast-flaming fires while reducing nuisance alarms from cooking. The unit includes a voice alert system that clearly announces fire warnings and end-of-life replacement reminders. Designed for easy installation, it features a large mounting base to cover drywall imperfections and a quick-connect plug. This tamper-resistant alarm is listed to UL Standard 217 8th Edition and includes a single button for silence and testing. Universal Security Instruments +4