EXTSW BEVELED 3/8” ID x 1 1/2” (1.490") OD x 1/4” Thick 316 Stainless Washer
Fits #613, 623, 713, 723 ARP Bolts
(Recessed .052" x .630" OD)  
(+/- .003" on all dimensions) 
.030 inch Radius OD / slightly countersunk ID (no sharp edges)
 Made in USA. 316 Stainless has the ULTIMATE corrosion resistance.