Forged Alloy Steel - Quenched and Tempered. 25% stronger than Grade 80. Individually Proof Tested to 2-1/2 times the Working Load Limit with certification. Recessed trigger design is flush with the hook body, protecting the trigger from potential damage. Easy to operate with enlarged thumb access. Positive Lock Latch is Self-Locking when hook is loaded. Eye style is designed with Engineered Flat to connect to S-1325 chain coupler. Suitable for use with Grade 100 and Grade 80 chain. The SHUR-LOC hook, if properly installed and locked, can be used for personnel lifting applications and meets the intent of OSHA Rule 1926.1431(g)(1)(i)(A) and 1926.1501(g)(4)(iv)(B). Fatigue rated at 1-1/2 times the Working Load Limit at 20,000 cycles. Look for the Platinum Color - Crosby Grade 100 Alloy Products." Forged Alloy Steel - Quenched and Tempered. 25% stronger than Grade 80. Recessed trigger design is flush with the hook body, protecting the trigger from potential damage. Easy to operate with enlarged thumb access. Positive Lock Latch is Self-Locking when hook is loaded.