EXTSW 5/16” ID x 1 5/8” OD x 1/4” Thick 316 Alloy Stainless Washers Actual dimensions .323 ID x .1.615 OD x .250 Thick(+/-.003 on all dimensions)Made in USA on a CNC latheIt is a beautiful fit for your 5/16“ Stainless boltsWe can make as many as you need, just contact me.(Not 18/8, Not 303, Not 304)316 Stainless Alloy is weldable and has the ULTIMATE corrosion resistance. 316 alloy cost more than 18-8, 303 and 304 and takes more time to drill and machine than the other alloys, but it is the best. Grade 316 is the standard molybdenum-bearing