The Astro Pneumatic 78804 3pc Ultra Thin Impact Sockets set comes with a protective sleeve and includes 17mm, 19mm & 21mm Sockets. This High-strength Ultra Thin Super Impact ring improves torques bearing capacity and color configuration ensures easy and quick size identification. Its special construction provides superior endurance over long-term use and lifespan up to three times longer than standard impact sockets. The unit maintains structural integrity under extreme heavy-duty applications w/thinner outer diameter allows for improved access to areas with tighter space. It includes a protective outer sheath which prevents damage to wheels and chrome; Outer sheath is transparent, making it easy to visually confirm socket condition, as well as special inserts to protect lug nuts and bolts.