Hoodman Glasses Model Hoodeye Eyecup for Most Canon SLR Models is specially designed for the eyeglass wearer. 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 bespectacled Canon SLR 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.