Allows to use M42 mount Camera Lens to L/M Lens camera.High quality provides great protection and shock absorption for your lenses waterresistant.Please note Infinity focus positionthe position of the infinity mark of the telephoto lens or super telephoto lens is shifted slightly to the positive side to enable focus adjustment even when focus shift is caused due to temperature changes.The shift range is denoted by an Lshaped line Be sure to check the focus through the viewfinder even when you shoot at infinity.Package includes 1 X Ring Adapter Mount