SlotRadio music cards are memory cards that are a pre-loaded with MP3 files, featuring artists from Billboard. SanDisk develops these music cards, which fit the microSD slots of cellphones and MP3 players.
A single music card can either contain 500 or 1,000 songs from hundreds of artists, eliminating the need to download new music. A music player plays the MP3 files on the card in sequence, and the songs are permanently locked to the card. A user can choose to play a particular song or skip through the files with a button. A classical music card can play up to 60 hours of non-stop music.