Zerust Gun and Rifle Barrel Rust Prevention and Protection Tubing (0.25" OD) - 10 Ft. Perfect for rust prevention on gun barrels, rifle barrels or lengths of stored metal pipe. Ready-to-use and easy to install. Air inside of the pipe is protected with vapor corrosion inhibitors It will never leave a residue, is non-toxic and will protect your gun and rifle barrel for up to 5 years Tube Diameter: .250"