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: Plastic Plug: US Voltage: AC 90-250V Frequency: 433MHz Power Consumption: 10mW Volume: adjustable, up to 110dB Music Selection: Support Chime Size (plug not included): 82 x 82 x 20mm or 3.2 x 3.2 x 0.8in Package Size: 9.5 x 9.5 x 7cm or 3.7 x 3.7 x 2.8in Package Weight: 100g or 3.5oz Package List: 1 x Plug-in Chime 1 x User Manual (English) Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.