The reusable metal straws are made of food-grade 304 stainless steel, which is scratch-proof, rust-proof and impact-proof. Reusable and environmentally friendly. The stainless steel metal straws are retractable with 3 adjustable straw lengths, perfectly compatible with 12-40 oz cups for almost any drink. Tight enough to avoid collapse. Our retractable metal straws feature an aluminum alloy shell and are specially designed for easy portability. The travel case is lightweight and can easily fit into your wallet, pocket, cosmetic bag, key chain, etc.