Features: 38 chimes with 3 level adjustable volume Long range up to 70m,sensing distance: 3-7 meters,highly sensitive doorbell receivers and transmitter . Humanized design, durable. Stable signal and strong penetrations insure you hear the bell and answer in time.Perfect for Convenience Store. Easy to install, no wiring required. Notice: Actual color may be slightly different from the image due to different monitor and light effect Please allow 1-3cm deviation due to manual measurement Specification: Receiver working voltage: 110-240V Transmitter working voltage: 4.5V (3 AAA batteries)(Not included) Receiver button: Music: 38 music optional, press the music button on the side to adjust Volume: Three levels of volume adjustment (high, medium and low) press side volume button to adjust Can be set to sound and silence (sound: sound + indicator silent: indicator) Working distance: up to 70 meters Transmitter sensing distance: 3-7 meters Receiver size: 76x80x33mm Transmitter size: 80x59x45mm Package List: 1x Doorbell receiver 1x Doorbell transmitter