Manufacturer ?secrui Part Number ?M520 Item Weight ?0.32 ounces Product Dimensions ?3.1 x 2.8 x 3.1 inches Country of Origin ?China Item model number ?M520 F55 Batteries ?1 CR2032 batteries required. (included) Is Discontinued By Manufacturer ?No Size ?1 receiver 1 button Color ?Black Material ?ABS Pattern ?Simple design Shape ?Square Power Source ?AC & Battery Voltage ?120 Volts (AC) Installation Method ?Self-Adhesive & Screw-In Item Package Quantity ?1 Temperature Range ?-4-140 Degrees Fahrenheit Sound Level ?120 dB Type of Bulb ?LED Performance Description ?MEMORY FUNCTION ENERGY-SAYING LED INDICATOR Accessory Connection Type ?Wireless Plug Format ?A- US style Switch Style ?Push button Special Features ?Adjustable Volume Optional Ringtone Usage ?Wireless Doorbells for Home / Classroom Doorbell Included Components ???1 × Transmitter (battery included), 1 × Plug-in receiver, 1 × Adhesive tape, 2 × Screw, 2 × Anchor, 1 × User manual Batteries Included? ?Yes Batteries Required? ?Yes Battery Cell Type ?Lithium Manganese Dioxide Description Pile ?CR2032 Average Battery Life ?3 years