WD-40 No-Rust Shield 3 In One Rust and Corrosion Inhibitor (Pack of 6) No-Rust Shield 3 In One Rust & Corrosion Inhibitor. Protects almost any metal against rust and corrosion. Place the shield in any enclosed 2 cu. ft. area for protection that lasts up to four months Non-greasy, no-odor formula provides invisible protection that seals metals from air and moisture Unique time gauge indicates when it is time to replace the shield.