The Old Skool 2 Player Link Cable is compatible with the Game Boy, Game Boy Pocket, Game Boy Color, Game Boy Advance and Game Boy Advance SP, and allows you to play multiplayer, as well as to transfer data.    With the Old Skool 2 Player Link Cable you can connect up to 2 systems simultaneously.
Compatible with Game Boy, Game Boy Pocket, Game Boy Color, Game Boy Advance and Game Boy Advance SP
Connect 2 GB/GBP/GBC/GBA / GBA SP systems together. 
Cable length of 5ft
Transfers data between systems. 
NOTE:   Not compatible with Game Boy Advance games!!!