Kidde 44037502 i9060 Premium Battery-Operated Ionization Sensor Hush Feature, 1-Pack Smoke Alarm, White Hush feature temporarily silences nuisance alarms Battery operated 9V battery included Test button tests unit's electronic circuitry Tamper resist locking pin helps deter alarm tampering and theft Kiddes smoke alarms meet the requirements of Underwriters Laboratories (UL), an independent facility that tests products for compliance with widely-accepted safety standards