This wireless doorbell operates without batteries, using self-generating power. It features 38 selectable ringtones and a strong wireless signal capable of penetrating walls. The system is easy to install and includes a memory function that retains your last volume and melody settings after a power outage. Color: White Material: ABS Type: Wireless Doorbell Power Source: Self-Powered Power Voltage: 110-230V Power Consumption: 0.25W Ringtones: 38 Doorbell Size: 4 x 4 x 5.6 cm / 1.57 x 1.57 x 2.2 in Receiver Size: 5.4 x 4.5 x 7.8 cm / 2.12 x 1.77 x 3.07 in With a reliable wireless range of 150 meters, the plug-in door chime ensures you hear visitors from several rooms away or another floor. The IP44 waterproof rating allows the doorbell to withstand various weather conditions, making it suitable for homes, offices, hotels, garages, shops, apartments, villas, gardens, hospitals, and schools. Installation is simple; just plug the receiver into a socket and fix the transmitter to the wall with the supplied accessories. Package Includes: 1 x Doorbell Transmitter 1 x Doorbell Receiver 1 x Instruction Manual