Eye Cup for Canon:
EOS-1D Mark IV, EOS-1D Mark III ,
1Ds Mark III, 7D, 5D
Eg Eyecup type 

Eyecup is a component that provides better contact with the head or glasses. With the right profile of the well adjacent to the eye, improving visibility in the viewfinder. In addition, prevents unwanted light to the viewfinder, which may have an effect on abnormal behavior.

Eyecup fits both left and right eye. 

Fit to camera:
CANON EOS-1D Mark IV, EOS-1D Mark III, 1Ds Mark III, 7D, 5D