As long as we have some eyepiece specialists gathered here ...
I have a DK-17M magnifying eyepiece (used with the D700/D3-4 style round screw in eyepiece adapters). That eyepiece, which is rather expensive, has a rubber "gasket" that protects eyeglasses. Mine is crumbling after about 8 years of regular use.
Anyone know if that gasket is a replaceable part?
In the interests of keeping the thread on track, I like the DK-17M, and use it with a surrounding round eye cup to further reduce glare. In principle that could be adapted to the DK-22, I guess, but it would stick out quite a bit, and probably slip off easily.
Thus I never used it on my D200 or D300. I used the magnifier designed for that eyepiece adapter but no longer use it for reasons probably more unique to the D300 than the D600, the view through an FX camera generally being "better suited" for that, for me, and other reasons.