Your Sony A200 is compatible with a widely used memory card format called CompactFlash (CF, as mentioned in passing earlier). Because it’s one of the oldest small memory formats, and because it’s a little larger, CF cards are generally less expensive than other options in the same capacity, so you can often get larger cards for less money than other formats cost. The CF card comes in two size types: Type I and Type II. Type II cards are more rare today, but Sony sells a Memory Stick Duo adapter (AD-MSCF1) that is a Type II card. Though this is a good option if you already have Memory Stick Duo cards, CF cards are generally less expensive than Memory Sticks. You might also want this adapter if your computer or peripheral exclusively uses Memory Stick Duo cards.