Cartridge or 2 CD / DVD (Standard Case) or 4 CD / DVD (Slim Case). Double walls protect from extremes in temperature and humidity. Outer wall absorbs impact much like a crumple zone in your car. Molded individual plastic slots eliminate shaking, or rattling. The cases come equipped with one padlockable hasp moulded directly into the case for superior strength. High quality single use seals are available to keep your items secure within your case. Manufactured of High-density polyethylene (HDPE) HDPE is a non-magnetizable, corrosion resistant material and has a high strength-to-density ratio with great durability, weather and wear resistance. It is commonly recycled, with the number "2" as its resin identification code.