Product Description 1. Press the button, super learning code can freely learn to match, can be unlimited matched receiver and button. 2. The transmitter without screw chuck design to achieve waterproof and dustproof.3. The wireless signal will be affected by obstacles. The more obstacles there are, the more severe the signal loss. Description: 1. The receiver can be hung on the wall or stand on the table. TheThe button can be attached to a wall or door using double-sided tape orScrew. Specifications: Model: A20 Power supply mode: 12V23A Supply voltage: 110-220 (V) Ringtone: 36 Power consumption: 1 (W) Scope: 200M open Type: wireless doorbell Color: black Package Included: 1 x Wireless Doorbell Set Notes: 1. Due to the difference between different monitors, the picture may not reflect the actual color of the item. We guarantee the style is the same as shown in the pictures. 2. Please allow slight dimension difference due to different manual measurement.