EXTSW 5/16” ID x 1 5/8” OD x 1/2” Thick 316 Alloy Stainless Washers
Actual dimensions .323" ID x .1.615" OD x .500" 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.