Smart Home Wireless Doorbell Features and specifications: 1.Press the button, super learning code can freely learn to match, can be unlimited matching receiver and button. 2.The transmitter without screw chuck design to achieve waterproof and dustproof. 3.The transmitter USE a 23A12V alkaline battery (not included battery). 4.The receiver uses 3 AA alkaline batteries, no need to plug in the power supply, and the battery can be used.(not include battery). 5.Receiving distance:300 meters in open area. 6.The wireless signal will be affected by obstacles. The more obstacles, the more serious the signal loss. 7.Receiver has 4 levels(can be mute) 20-80db,36 music to choose from. 8.Transmitter size:77*46*20mm 9.Receiver size:95*65*24mm 10.Just plug the receiver into an electrical outlet,the push button transmitter can be stick it to the door with provided adhesive tapes. Note: The button cannot be placed on an iron door because it will interfere with the signal. If the receiver does not ring when you press the button after receiving the doorbell, please check the steps: 1. Please confirm whether the button has a 23A12V alkaline battery installed. 2.Check if the receiver has a 3*AA alkaline battery installed. 3. Please pair the doorbells again. How to pair signals Press and hold the volume button of the receiver and the transmitter for about 8 seconds to successfully pair. How to modify and lock music? Press and hold the receiver's volume and music buttons before plugging in the power outlet. Plug in the power outlet until the receiver light is on, release the volume and music buttons, and press the volume button again. Press the music button to adjust to your favorite music ringtone, press and hold the volume button again until the indicator lights up, immediately press the transmitter twice and the music is successfully locked. ?