Includes a built-in 90MB memory to store up to 25 songs with crystal clear?? MP3 playback</br>Transfer MP3 song files from your PC to the internal memory via the included USB cable</br>Easy wireless installation mounts to walls</br>Clear?? crisp sound via the built-in speaker makes this an ideal portable MP3 player</br></br>Product Description</br></br>Swann SWHOM-DC840B MP3 DJ Wireless Music Doorbell  Features:-  Say goodbye to the boring 'ding-dong' doorbell -  Just like your mobile phone's ringtone?? you can now personalize your home doorbell -  Includes a built-in 90MB memory to store up to 25 songs with crystal clear?? MP3 playback -  Transfer MP3 song files from your PC to the internal memory via the included USB cable -  Easy wireless installation mounts to walls & runs from 3 x AA battery power (battery not included)  -  Includes easy to use MP3 editing software for adjusting your songs & tunes -  Clear?? crisp sound via the built-in speaker makes this an ideal portable