Universal Security Instruments Hardwired 10 Year Tamper Proof Permanent Power Sealed Battery Photoelectric Smoke and Fire Smart Alarm, Model MP116S Smart Alarm Technology provides peace of mind with this alarm  Fast-and-easy installation suitable for houses, apartments, dormitories and more Fully interconnectable with up to twenty-four USI-compatible devices Tamper-proof design provides a higher level of security and prevents battery removal Eco-friendly design reduces environmental wastes and eliminates disposal of excess batteries Comes with a ten-year limited warranty