EXTSW 1/2” ID x 7/8” OD x 3/16” Thick 316 Stainless Washer
Actual size .507" ID x .865” OD x .188" 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.