Quantity: 1 piece (battery not included) Power supply: 2 AAA (or No. 7) alkaline batteries Battery life: Standby for more than 2 years (5 times a day on and off) Ambient temperature: - 10~ 60C Ambient humidity: <80% Storage temperature: -20C~ 70C The magnetically triggered door alarm sensor protects the house through the door and window entry, suitable for safe, wardrobe, freezer, refrigerator, freezer, swimming pool sliding door, store, office, apartment, hotel, etc. 4 in 1 Multifunctional and easy to use: 4 modes for your many choices: general alarm, continuous alarm, time delay (closing alarm doorbell) and doorbell, just press the button to select the function you want, no need to choose which setting. Certainly. 108dB Loud Enough Home Security: Door and window alarms help effectively deter intruders/thieves with a loud 108dB alarm. EASY INSTALLATION PROFESSIONAL SECURITY SYSTEM: Easy peel-and-stick installation and low power consumption design provide convenient and long-term protection.Good quality product