Make sure the safety of your propane cylinders with these protect caps. The outdoor aluminum alloy magnetic air tank cover is made of aluminum alloy, iron, strong magnet, and silicone. It is lightweight and portable, with a super strong magnetic force and wear-resistant. The pack includes a magnetic canister cap. Note that due to different lighting and screen settings, the item color may be slightly different from the picture, and due to different manual measurements, please allow a 1-2cm difference in size.