Metallics JWW83SS Washers 1/2 USS Flat SS (Jar 100)

Solid stainless steel, not plated. Material and finish are both stainless, so there is no coating to scratch through and start rusting at the wrench marks. That makes them the pick for exterior mounting, damp mechanical rooms, coastal work, or anywhere a zinc washer under a stainless bolt would be the part that fails first.

USS is the wider, thicker pattern. The JWW83SS is a USS flat washer, meaning a larger outside diameter and more bearing surface than the SAE pattern in the same bolt size. That is what you want when the bolt is going through wood, sheet metal, strut, or an oversized or slotted hole and the load needs spreading. Use SAE instead when the clearance around the hole is tight or the washer has to sit inside a counterbore or under a small flange.

Match them. The JWW83SS is stainless through and through, so pairing it with stainless bolts and nuts keeps the whole assembly one metal and avoids the galvanic mismatch you get when a zinc plated washer sits between a stainless bolt head and the work. If your bolts are hot dip galvanized, stay with galvanized washers instead.

Washer thickness runs 0.132 to 0.086 inches. That matters when you are stacking up a bolt length: two of these plus a nut eat close to a quarter inch of grip, so check your remaining thread engagement before you order bolts.

100 washers per jar, packed in a jar rather than a bag or a box, so it stays closed on a service truck and pours one handed. Total shipping weight of the jar is 1.69 lbs.

The jar measures 4.57 by 3 by 3 inches, so it drops into a standard van shelf bin or a deep tote without decanting. Worth knowing before you order a dozen jars for a stocking run.