This is a custom-made cap to perfectly fit this lens. It has large, easy-to-grip handles that are spring loaded. It attaches to the inside ring on the end of the lens and can be used with or without the factory hood in shooting or storage position. The front is flat so you can put the lens dian on a flat surface without tipping. It is much easier to use than the factory cap and can even be used without taking off your gloves. It is made of high strength fiber-reinforced polymer that can withstand high heat and impacts without damaging your lens. It is made in USA and comes with a lifetime no-hassle warranty against accidental damage to the cap.