EXTSW 1/2” ID x 1 ” OD x 3/16” thick 304 alloy stainless washer
Actual size .507" ID x .990” OD x .188 thick
(+/- .003" on all dimensions) 
.030 inch Radius OD / slightly countersunk ID (no sharp edges)
 Made in USA. 304 Stainless has very GOOD corrosion resistance.