This is a set of Stainless Steel Front and Rear Wheel Bearing Shims. They will fit all triple and late 750's together with the 500 models all the cast wheel machines infact. (not Zane twins). They will not fit any wire wheel machine.  The original parts numbers are 33270011 x 2 and 33270012 x 2. These go in behind the wheel bearings and they hold the central spacers in place, they always get damaged when you replace the wheel bearings. As far as we know we are the only source of these. Put some on the shelf because once our stock has gone they may not be re-made any more.