remote control doorbell (smc-2017)

This product is suitable for home, hotel, hospital ect;
Sound category: Single Dingdong, Double Dingdong, 12 songs,
Sender: DC 6F22 9V; receiver: 2pcs AA batteries;
Frequency: 433. 92MHz
Remote Control Distance: about 30M
Use digital codes to avoid interference
One sender can control one or more receivers