Product name: DC wireless doorbell Operating frequency: 433.92MHz Transmitter size: 63mm*39mm*17mm Receiver size: 107mm*53mm*24mm Working distance: open 200 meters Launcher Features: 1. Adopt long-life capacitive touch buttons 2. Ultra-low power consumption design battery can be used for 3 years 3. Adopt IP65 waterproof and dustproof design 4. Use millions of learning codes without repeating codes Receiver Features 1. Adopt dual-mode intelligent code learning mode 2. 17 months standby time with ultra-low power consumption design 3. Open 200 meters ultra-long receiving distance 4. 38 polyphonic music and flashing blue light 5. 5-step volume adjustment and mute function 6. Power-off memory and song volume reset function Instructions: 1. Song selection: Press the button to switch to the next music, a total of 38 loops 2. Volume adjustment: press the volume key, the volume can be adjusted from high to low five gears 4-3-2-1-0, 0 is the mute state 3. Reset function: long press the select button for 3 seconds, it will automatically reset to the first music and the maximum volume 4. One-to-one mode: Press the volume key and the song selection key at the same time, enter the learning code mode with a beep, then press the transmitter again, and the code is successfully ding-dong. If the code is not successfully matched within 5 seconds, it will exit with two beeps. 5. Multi-drag one mode: After selecting the desired song, press the volume key for 3 seconds, enter the learning code mode with a beep, and then press the corresponding transmitter, the code is successful. If the code is not successfully matched within 5 seconds, it will exit with two beeps. Same as above, select another song, and learn the code from another transmitter. You can learn up to 15 launchers.