These USAE washers are a hybrid of USS standard washer and SAE attributes. They have more contact area and greater holding power with a USS-standard outside diameter, offering washers up to 36 percent larger than regular hardened washers. The inside diameter fits SAE standards, making a smaller ID for a more precise fit on bolts and studs. All American made, the USAE washers are made out of mild steel, case-hardened to 60 HRc and have a black oxide finish. They are 37 percent thicker than standard washers. They come in a range accommodating bolts from ¼ to 1 inch, with the bolt size stamped on each washer. Tolerances on all USAE washers are ±.010 inch.