These shackles are designed with an increased bow radius and oversized bolt, because a wider bearing surface promotes longer sling life. They feature an all alloy construction for durability, and each shackle is traceable with a PIC code. Using such a shackle means you retain the full strength of your sling (be sure to use the right size shackle to pair with your sling's rating). Safety factor of 5:1. These shackles are ASME B30.26 compliant.