Hex Flange Grade G All-Metal Lock Nuts feature a crimped locking top section and an integrated flange that functions as a washer to increase the lock nuts bearing surface. The crimped top section is slightly deformed to provide a very strong and highly vibration resistant connection when wrenched into place. The integrated washer flange distributes the clamping load over a larger area for a more secure connection. Grade G Flange Lock Nuts are commonly used with Grade 8 Flange Bolts to create secure vibration resistant connections on truck frames and other heavy equipment. Grade G lock nuts have a material Proof Load of 150,000 PSI and a strength equivalent to Grade 8 hex nuts. They feature a Black Phosphate and Oil finish as standard.