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 or White (Optional)Material: PlasticPlug: UKVoltage: AC 90-250VFrequency: 433MHzPower Consumption: 10mWVolume: adjustable, up to 110dBMusic Selection: SupportChime Size (plug not included): 73 x 73 x 32mm or 2.9 x 2.9 x 1.3inPackage Size: 8 x 8 x 5.5cm or 3.1 x 3.1 x 2.2inPackage Weight: 75g or 2.6ozPackage List:1 x Plug-in Chime1 x User Manual (English)