This hooks are made of PA12(Plastic). Convenient & Practical: String lights hanging hooks 40-Pieces, use a phillips screwdriver can easily screw the nail into the wooden beam or tap it with a hammer and tighten it again. Widely Used: Beautiful and suitable for hanging a variety of items. (outdoor holiday Lights, drip line, potted plants, bird feeders, cords, chains, wind chimes, light fixtures, etc) Anti-Drop Design: Windproof and rust-proof hanger, the open-loop design can prevent items from falling off and make it easier to replace o r take out items. Light & Strong: Under the small handle, a high-strength stainless steel shrapnel is installed. can easily open it, and closed well automatically., the hook can withstand Max 16.5 pounds, suitable for indoor and outdoor use.