The plug-in chime will be activated when a visitor is pressing the smart doorbell. Plug-in chime is a practical tool that matches with smart doorbell, and they both provide home security for you Features: 433MHz frequency, compatible with wireless video doorbell. Plug-in chime, easy to use, designed for indoor use only. Adjustable volume, low to mute, up to 110dB. Different melodies for selection, meeting various needs. A chime can pair with multiple doorbells, a doorbell can pair with multiple chimes. Note: Size and color may be slightly different due to manual measurement and different light conditons or other reasons, please in kind prevail. Thanks for understanding. Specifications: Color: Black/ White (Optional) Material: Plastic Plug: UK Voltage: AC 90~250V Frequency: 433MHz Power Consumption: 10mW Volume: adjustable, up to 110dB Music Selection: Support Chime Size (plug not included): 73 * 73 * 32mm / 2.9 * 2.9 * 1.3in Package Size: 8 * 8 * 5.5cm / 3.1 * 3.1 * 2.2in Package Weight: 75g / 2.6oz Package List: 1 * Plug-in Chime 1 * User Manual (English)