I have a large number of these discs but no idea just what they were used on. The discs are 3" in dia with the holes 2-1/4" across the center from 11 oclock to 5 oclock about 1/4" thick, they are hard with string woven in them. They may be used as a coupler to a water pump or some other type of unit. The only thing is that don"t have any give or flexiblity to them. Click on thumbnail to enlarge. Thanks!!! 1-262-392-2989 or mribbich@wi.rr.com Marv.