Never knew they made a DAT walkman, I do remember coveting my friends sports walkman, the waterproof possibilities of swimming to Micheal Jackson thriller was a tempting thought, actually i still is.
I have a WM-2. -F77 and a couple other Sonys* plus a Cybernet with vinyl case that works great except one belt, talk line and two phone jacks it anybody wants to add to their collection at a low price...hint hint.
Got a WM-DDIII. Payed 40 euro for it, but it had the clicky quartz lock problem. Fortunately the seller was nice enough to fully refund it, but getting this repaired is not cheap I think.