lock is made of high hardness steel material. Using polishing process, durable. You don't have to worry about it rusting.The heavy-duty carabiner has passed the breaking strength test of 440 pounds, and the recommended working load limit is 400 pounds. Allows quick connection/disconnection. For more safety, we also added a screw lock function to the carabiner.304 stainless steel screw lock carabiner hook is suitable for outdoor work, hanging hammocks, hanging swings, etc.screw lock and spring clip lock make them safe and convenient. Allows quick connection/disconnection, matching with swing swivel, this carabiner is perfect for hanging ropes, hoses and other items.Colour:SilverMaterial:steelPackage Contents:9 * Spring claspOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.