I recently purchased and received the SP-445 adapters. On my first attempted use of them I found one of the adapters worked perfectly. The other one must have been printed on a different 3D printer as it was of different dimensions. The Zebra glass plate only slid into the adapter with a large amount of pressure. I was slightly worried about breaking the plate. I think this might wear in with continued use and become easier to insert plates. The real issue was that it is wider than the other plate. The photo below shows the wider plate and was taken after I filed the edges down enough for a tight fit. It simply would not fit into my Stearman Press tank until I filed the edges down. Even now it takes much pressure to slide it into the press. They do function but the manufacture of the wider holder could have been controlled better.