Forged Alloy Steel - Quenched and Tempered. Individually Proof Tested to 2-1/2 times the Working Load Limit with certification. Each hook has a Product Identification Code (PIC) for material traceability, along with the size and the name Crosby. Hoist hooks incorporate two types of strategically placed markings forged into the product which address two (2) QUIC-CHECK features: Deformation Indicators and Angle Indicators. Low profile hook tip. New integrated latch (S-4320/S-4339) meets the world standard for lifting. Heavy duty stamped latch interlocks with the hook tip. High cycle, long life spring. When secured with the proper cotter pin through the hole in the tip of hook, meets the intent of OSHA Rule 1926.1431(g) and 1926.1501(g) for personnel lifting. Suitable for use with Grade 100 and Grade 80 chain. 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.