This hook holder contains rust-preventive paper, making it less likely for your hooks to rust! Furthermore, it floats in case you accidentally drop it in water, providing peace of mind. This rust-preventive hook holder allows you to compactly store bulky hooks. How the rust-preventive paper works: The rust-preventive components in the paper vaporize and adsorb to rust-causing factors on the hook surface and inside the hook holder, preventing rust. Therefore, it is effective even if the rust-preventive paper and the hook are not in direct contact.