【Product Features】 Wireless design: easy to install, suitable for any door and window environment, no wiring required, and can be used at any time. Long-distance transmission: The wireless distance can reach 100 meters (in open space), which is stable and reliable and can meet the needs of various scenarios. Ultra-long battery life: Using CR-2032 batteries (2 pieces), low power consumption design, battery life exceeds 3 years, eliminating the trouble of frequent replacement. Dry contact switch: With high sensitivity and stability, it can accurately detect the open or closed status of doors and windows and seamlessly connect with the intelligent system.