Founded in 1917, Kidde is the world's largest manufacturer of fire safety products. Kidde fire safety products are found in homes and businesses around the world and help to prevent injuries and damage by alerting people to dangers earlier. The photoelectric sensors in the P3010L detect visible particles and are best at detecting smoldering fires. The battery powered P3010L will continue to protect you even in the event of a power outage. With a sealed 10 year lithium battery, the need for battery replacement is eliminated. Product Information: Sealed Battery With a tamperproof, sealed lithium-ion battery, the battery on the P3010L cannot be removed, making it perfect for apartments, hotels or dorms. Hush® Mode The P3010L feature End of Life Hush®, allowing you to silence to alarm for three days at a time for up to 30 days before replacing the alarm. End of Life Signal The P3010L has an audible "end of life" notice after 10 years when it needs to be replaced. Alarm Reset The P3010L will automatically reset when the smoke clears. Battery Backup The battery powered P3010L will keep you safe even during power outages. Covered Under a 10 Year Limited Manufacturer Specifications: Power Source: Battery Battery Requirements: 1 Lithium Ion Battery Diameter: 5-1/4" Depth: 1-5/8" Voltage: 120V