These are special designed wireless mp3 doorbells. They have MP3 or WMA playback function and come with a loud speaker. Moreover, they are suitable for users to put their favourite MP3 music as the doorbell sound and users can adjust the volume as they like.

• Power: transmitter
• Battery used
• Receiver can work alone as a mp3 player
• Receiver: AC power
• Wireless frequency
• 433.92 mhz