EXTSW 5/16” ID x 1 1/8” OD x 1/8” Thick 316 Alloy Stainless Washers
Actual size .323" ID x 1.115” OD x .125" thick 
(
(+/- .003" on all dimensions) 
.030 inch Radius OD / slightly countersunk ID (no sharp edges)
Made in USA. 316 Stainless has the ULTIMATE corrosion resistance.