This is the hoodeye for canon 5d 5d mark ii cameras this eyecup is a great way to prevent excessive ambient light from entering your viewfinder by removing your cameras eyepiece and substituting the hoodeye you can improve your viewfinder clarity this item is camera specific please make sure you get the one that fits your camera note will not fit the 1d and 1d mark iii rotates to accommodate both right and left eyed shooters