Features: 100% brand new, high quality Suitable for home, office indoor use, not for balcony where has insolation or rain. Compact, wireless, easy to install. Low power consumption, lasting one year. to change batteries frequently. Powered by 2 pieces of AAA alkaline batteries. (Batteries are not included in the pack.) Low power remind with LED indicator Super loud alarm of 105dB, scare thief away Magnetic sensor, door and window motion detector. Keep the distance between device and magnetic shorter than 10mm, and arrow aims to each other. Make sure one install in door/window, another one install in door/window frame, that to let them separate when the door/window is opening. Specifications: Material: Plastic Working Temperature: -10 ~ 60C Working Humidity: below 80% Size: approx. 8.5 x 4.3 x 1.5cm Color: White Net Weight: 37g Package includes: 1 x Main Device 1 x Magnetic