RAM expansion for the Amiga 500 which connects to the side expansion slot and supports up to 8MB of additional RAM. The unit also had a through-port so that other devices could also be plugged into the side of the A500. Depending whether you bought the unit with 2, 4 or 8MB of RAM it was called the AX502, AX504 or AX508, all of which are exactly the same device. For details on the AddHard shown in the picture, please consult the section on SCSI controllers.