This Nikon DK-21M Magnifying Eyepiece magnifies the images in the camera's viewfinder by approximately 1.17x and is compatible with select Nikon DSLRs.
Compatibility
Nikon D40, D40X, D80, D90, D200, D300, D300S, D5000, D7000, D7100, D7200, D7500, D3000, D3100, D3200, D3300, D3400, D3500, D600, D610, D750.