Tronixpro 72mm Pro Series Snap On Lens Cap For Sigma 18-35mm f/1.8 DC HSM Lens, Sigma 18-35mm f/1.8 DC HSM Lens, Sigma 17-70mm f/2.8-4 DC Macro OS HSM Lens This lens cap protects lens surface from dust & shock during storage. Unique snap on design allows easy installation onto the lens & one-step removal from the lens. It fits directly onto the lens with a double-action spring design. Microfiber Cloth 72mm Snap On Lens Cap