2PCS penetrating remote control smart wireless doorbell, anti-interference function, easy to install Product name: Wireless doorbell Colour: Black Material: plastic + electronic components Transmitter power supply: 1 x 12V/23A battery (not included) Receiver power: AC power Transmitter size: approx. 75 x 51 x 20 mm / 1.77 x 0.87 x 3.11 inches Receiver size: approx. 95 x 65 x 24 mm/2.24 x 0.98 x 3.94 inches Weight: 0.45kg describe: This wireless doorbell includes an outdoor transmitter and an indoor receiver. Built-in 38 ringtones can be switched. The home call system for patients or the elderly is also great. feature: 1. The penetrating smart wireless doorbell can receive signals within 300 meters. 2. Digital circuit design, anti-interference function, the doorbell will not ring by mistake. 3. Tell the visitor whether to press the doorbell successfully or incorrectly through the LED light. 4. Built-in 38 tunes, you can choose your favorite tunes at will, and switch ringtones as you like. 5. The volume is adjustable in 3 levels to meet different needs and ensure warnings. 6. The indoor receiver uses AC power supply, plug and play, which is very convenient; the outdoor transmitter needs battery power supply, with stickers and screws, easy to install. Scope of application: suitable for homes, offices, villas, hospitals, factories