Wireless Doorbell Set Selfpowered Remote Button Receiver Features: The doorbell adopts wireless high-frequency emission technology, effectively avoiding the troubles caused by mutual interference between neighbors and false alarms. Easy to mount and requires no wiring, simple and fast installation. In addition to being used as a doorbell, it can also be used for special purposes such as contact, paging, patient care and emergency notification. The wireless doorbell can be installed at will, and the button can be installed or pasted. It is suitable for home, office, hotel, building, dormitory, factory, construction site or any space that needs service. Specification: Material: ABS Color: Main White Transmitter Power: <10mW Receiver Volume Range: 25-75dB Receiver Standby Current: <1.0mA Transmitter Size: 8.1*4.9*2.1cm / 3.2*1.9*0.8in Receiver Size: 8.1*4.9*2.1cm / 3.2*1.9*0.8in Number of built-in MP3 ringtones: 16 (external extended ringtones are not supported) Package Weight: Approx. 154g/5.4oz   Package list: 1 x Self-powered Transmitter 1 x Wireless Plug-in Receiver 1 x User manual   Note:  Due to the difference between monitors and light effects, the pictures may not reflect the actual color of the item. Please allow slight measuring error due to manual measurement.  Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.