I am trying to find some B2 focusing screens, and I find a lot of listings on eBay. But even though they are listed as B2 and have B2 boxes, they all look like the K-type to me based on the MIR site. Am I wrong? I am guessing when people put their new B type screens on their cameras, they put the K-type screens into the B type boxes for safekeeping, and now they are all mis-listed:
https://www.ebay.com/itm/Mint-Nikon...901748?hash=item5487575a34:g:fq0AAOSwJddfDZCD
https://www.ebay.com/itm/Mint-Nikon...901748?hash=item5487575a34:g:fq0AAOSwJddfDZCD