Hook Automatically Closes And Locks When Loaded Makes rigging safer and easier When closed, hook stays attached to load even when tension is off Spring loaded latching mechanism Safety release thumb tab Grade 100 heat treated alloy steel Solid forged steel clevis and pin Fits 9/32", 3/8", 1/2", or 5/8" G100 Chain Safe Working Load: 4300 lbs, 8000 lbs, 15000 lbs, or 22600 lbs