Those are hard to find, but I think you'll have more trouble finding a system card by itself, but I could be wrong. I lucked out and found my cd unit at a flea market with carrying case, system card, and a few odds and ends for $20. I had to order a new AC adapter for it and have it repaired, but it works fabulous. I still bought a brand new Duo about a year later, cause I didn't think I would ever find a 3.0 card, at least not cheap.