Vinker 2 PACK Wireless Automatic Magnetic Cabinet Door Contact Sensor for Home Security Alarm, Independent Door & Window Alarm (MG-C) Magnetic sensor switch detects entry protecting your home or office Home TO use: Protects exterior doors, sliding glass doors, gun and medicine cabinets.Commercial use: Protects showcasesand cash registers Usage: window and door Easily mounted by adhesive tape to a window or door,Easy to installation,no wiring. Powered by 3pcs 1.5V button battery(included), long battery life Up to One-Year.