I have this excellent condition close-up filter set for TLRs, comes with original box and plastic case as shown.

From some online searching, it seems to fit early Mamiyaflexes, maybe the Yashicas with slip-on filter setups like the A/B models (doesn't fit the 127/4x4/Baby Yashicas). It's the Type B so it will not fit the style of TLR that has taking-lens-only focusing like the Argus Super Seventy-Five. I'd venture that it's a 28.5 slip-on fit.

Shoot me trade offers: film, filters or hood to fit Ikonta 521A, front element for a Jupiter-8 are some ideas.