This bolt works with the H170 shackle. Unlike S-hooks they can be used multiple times. They are also much easier to install and uninstall then S-hooks. They are stronger and some cities and parks are requiring their use instead of S-hooks. This shackle is 5/16” with 3/8” x 1 ½” bolt. There is a ½” opening at the bolt and at the widest it is 1”. This will accept up to a ½” chain. This product should last 2 years in harsh conditions and up to 5 years in optimal conditions. Some conditions may require replacement sooner. Tensile strength 12500 lbs.