This vintage memory expansion board is an essential item for Apple enthusiasts. It is designed to fit perfectly with Apple products, particularly the MAC Classic. This board is model number 661-0598 and has part numbers 820-0405-01 and 630-0405-S2. The board has a capacity of 1MB and is compatible with various Apple products. It is a must-have item for anyone who is interested in collecting or restoring vintage Apple products. This memory expansion board is in excellent condition and is ready to be used.