Sorry for the late reply. 1. The Mark IV 1162/173 can be found on both Etsy and EBay, it will fit all Uncle Seiko Speedmaster bracelets that taper to 16mm. They are genuine and include the whole clasp. Internal diameter is 16mm, external 17mm, length about 34mm. They are almost identical in size to the stock Uncke Seiko clasp covers. These really suit the US1711 bracelet very well. 2. The “Speedmaster 1171 Moonwalk deployment clasp” should be avoided. They are genuine but the internal width of the clasp cover is only 15mm. External diameter is 16mm. They are too small. Someone correct me if I’m wrong. 3. The “Canada clasp cover” is a $20UD clasp cover only, which I believe, but cannot prove are non genuine but still of a pretty good standard https://www.ebay.com/itm/Original-V...869324?hash=item3daa7610cc:g:s3MAAOSwJ9RdKN7v For me, the polished outer edge and brushed inner portion is very reminiscent of the clasp covers found on the old flat links and suit them very well, though they will fit most US bracelets that taper to 16mm .