The Kidde P3010B is a 10-year, sealed battery, smoke alarm with photoelectric sensing technology and Smart Hush feature. The 85dB alarm tone is accompanied by a voice warning feature. The alarm will automatically activate when attached to the mounting bracket. At the end of the alarm life, the unit will chirp, indicating the alarm is in need of replacement. The 10-year tamper-proof battery eliminates the need for replacement batteries and ends worry of unauthorized battery removal. Provides continuous protection, even during power outages.