Features: One million sets of non-repeated operation password to ensure interference-free operation. You can select 16 different sounds yourself by pressing the red button of the remote control. Maximum remote control distance of up to 300m free to air. Take your door chime with you around the garden and avoid missing visitors. No wiring required simple to install. Specifications: 1. Transmitter: Voltage:  DC 3V (CR2032) Quiescent Current:  ≤ 1uA Working Current:  < 4 mA Operating Frequency:  433.92MHz±50KHz Power Consumption:  < 10dbm Transmission Interval:  ≈ 2.2s Transmission Range:  ≥ 393ft/120m (open area) 2. Receiver: Voltage: DC 4.5V 3AA Standby Power: ≤ 0.1W Working Power: ≤ 3.5W Volume: > 80db