Crosby® Screw Pin Sling Saver Shackle | S-253 - 4"- 20.5 TonCrosby S 253 20. 5 Ton Web Sling Shackles For High Capacity Synthetic Sling Connections Designed for serious lifting applications, the Crosby S 253 Web Sling Shackle features a squared bow profile specifically engineered for synthetic slings. The wide contact surface eliminates bunching and sliding while allowing the sling to fully engage its rated capacity boosting sling efficiency by at least 15% compared to traditional shackles and hooks. This