Hoodman's Hoodeye Eyecup for Canon 5D, 5D Mark II, 6D, Rebel T3/1100D Models will help block out light when looking through your camera's viewfinder . From its over-sized design, which seals out ambient light, to its rotating nature that accommodates right or left eyed shooters, this eyecup ensures that the Canon 5D, 5D Mark II, 6D, and RebelT3/1100D shooter can get their shot with ease. The self locking mount slides over the eyepiece mounting rails, keeping the cup in place. Additionally, the hypoallergenic silicon keeps irritation at bay for hours of comfortable shooting.