Feature: 1. Self Powered Design: Utilizes solar energy for automatic charging, no batteries required, environmental protection and energy saving. 2. Improved Function: One receiver can connect to two doorbell buttons, covering a wider area, convenient for multi story buildings use. 3. Smart Elderly Caller: The unique design allows elderly people living alone to call their loved ones at home in a convenient and quick way. 4. High Reliability: Long distance self powering, no external power source needed, convenient for remote operation, suitable for various outdoor scenarios. 5. Modern Appearance: Simple white appearance, suitable for EU plug 90 to 260V, blends well with modern homes for a more aesthetic look. Specification: Item Type: Wireless DoorbellMaterial: ABSPlug: EU Plug 90 - 260VTransmitter: Battery type: Lithium battery, Battery Capacity: 150mAh (Shipped with built in battery) Receiver: Working current: ≤60mA, static current: ≤10mA Power: ≤2W Music: 52 songs Operating Frequency: 433MHz Adjustable Volume: 20-80dB(4 speed cycle adjustment) . Package List: 1 x Transmitter 2 x Receiver 1 x Base 1 x Double Sided Tape 2 x Screw 2 x Expansion Bolt 1 x Multilingual User Manual