Forged alloy steel, quenched and tempered. Each hook has a product identification code (PIC) for material traceability, along with the size and the name and USA in raised letters. 25% stronger than grade 80. Eye sling hooks incorporate two types of strategically placed markings forged into the product which address two QUIC-CHECK® features: deformation and angle indicators. Low profile hook tip. Utilizes S-4320 integrated latch which 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) for personnel lifting. Individually proof tested to 2-1/2 times the working load limit with certification. Suitable for use with grade 100 and 80 chain. Fatigue rated at 1-1/2 times the working load limit at 20000 cycles.