USB Power Home Wireless Doorbell Remote Control Intelligent Flashing Doorbell Caller 1. USB power supply voltage: DC 5 V 2. Fixing method: double-sided adhesive tape 3. Receiving distance: 200 m (open area) 4. Host power supply: USB power supply 3 x AAA battery (not included) 5. Key power supply: 1 x CR2032 button battery 6. Size: main body about 8.4 x 5.4 x 2.2 cm, key about 6 x 4 x 1 cm Features: 1. ABS shell, flame retardant and high temperature resistance, cold and low temperature resistance, anti-oxidation and corrosion resistance, environmentally friendly and recyclable 2. Ringer + colorful flashing light, 3 modes to choose from, ringer + flashing light, ringer only, flashing light only 3. Mode switching method: press and hold the music key and volume key at the same time for 1 second to switch 4. 38 chord music ringtones, large diameter speakers, pure and beautiful sound quality 5. Wireless installation, simple operation, press the doorbell button, the host bell ringing