Features: Autonomous, no wires; Mains powered speaker (socket); Battery operated button (battery included; service life 1 year); Working radius - 300 meters. Waterproof button and IP44 (not afraid of wet rooms); 4 levels of volume control from 0 to 100 dB (that's too loud) with speaker + mute control; Mains powered speaker (socket); Button temperature range: -20°C to +60°C. Receiver temperature range: -10°C to +55°C. 36 sweet tones; Installation without drilling and wires, adhesive plate or self-tapping screws in socket and radio button; Musical, loud speaker, selection of tones; Modern and elegant design, rounded body; Protected against accidental activation if a neighbor installs the same or similar electric doorbell; ? The transmitter and receiver are easy to set up with each other. You can connect up to 8 buttons to one receiver. 1 button can be associated with multiple receivers, multiple pairs of calls will play simultaneously when pressed? Can it be used as an alarm and warning system for staff, employee, pager, remote emergency alarm to help sick customers, disabled, deaf, patient, administrator, waiter? The waterproof bell can be installed on the entrance doors of the apartment, country house, gate, and also suitable for the street, private house, any doors, apartment, country house, street gate at the entrance, bathroom and toilet, care for the needy, disabled, deaf. Electronic, flashing, wireless, door, apartment, street, wireless, electric, waterproof, water-resistant, moisture-proof regulator and light lamp tone set, table, exit, gate, door, fence, wireless, strong network household and bell. There are also other cordless electric bells with a kinetic button and a battery. If you have any questions about the device, write through the form "ask the seller about the product" and we will definitely answer you during working hours, within one hour!