I never understood what was going through the minds of Sony engineers when they released this one, especially since 3-1/2" CDs were never a real, viable thing—even back in the day. I believe had one in my old collection (A Touch of DMP), and that was a free sampler that came with a regular CD I'd bought. You're never going to pop this in your pocket or bag and play regular-sized CDs, but yet they are quite popular with collectors and go for a lot of money on the used market.