Features: Can be used in restaurants, coffee shops, cafes, factories, banks, bars, discos, billiard rooms, hospitals, clinics, senior homes, etc. Wireless and easy to use, no string code needed. Comes with double-sided tape for easy installation and direct application. It has a one-touch call function that can be used with the host side. Uses SAW DEVICE Air-Communication Parts, ensuring signal transmission Stability: Built-in channel anti-mix function, built-in timing circuit design Specifications: Condition: Brand New Material: ABS Product Features: Product calling function can be customized Reception distance: 1000 meters in open area, 40-80 meters indoorProduct size: about 86*86*15 mm /3.4*3.4*0.6 inches Product color: white flip frequency band: 433MH2/315MHZ call function: call cancel button: 2 buttons : All receiving hosts of the brand. Same power supply: 12V 23A batteries included: Original imported chip reception principle: aviation specific transmission frequency Product operation: can be changed number and reusable. Weight: about 86g/3oz Package list: 1 * Alarm (with battery) 1 * Double-sided sticker