Insten EyeCup Compatible with Canon EF 500D 450D Rebel T1i XSi XTi XT XS Accessory ONLY, camera is not included. Overall Dimensions: 40mm x 24mm. Color: Black. Refer to your Canon's user manual or manufacturer to ensure compatibility. This 18mm Eyecup for Canon replaces your lost, damaged or broken eyepiece. Features a soft outer edge rubber cushion. Two small clips on the back secures the eyepiece onto your camera. Interior Dimensions: 17.3mm x 11.7mm.