My last acquisitions are two prototypes for the upcoming RevoRings from H&Y:
from 46 to 62mm, with a single 67mm ring)
I really like these. The bottom one is the simplest. What it does is provide an adjustable ring so that you can use a single filter and mount it on lenses with varying filter diameter sizes (that one covers from 46 to 62mm, with a single 67mm filter).
The top one is basically the same (except that this model is larger, going from 67 to 82mm) except that it includes a variable ND filter / circular polarizer. The included filter appears to be high quality.
The RevoRing works by using "claws" which grip the inside of the lens front (where the filter threads is) so they can adapt to several sizes. The grip is strong but not too much, it won't damage the threads. It means you cannot use a hood, but it also means you can purchase a single, high quality filter, and use it on many lenses. It also means you can swap in seconds, which can be a godsend for landscape photographers.
Oh.
One more thing.
I also received the DFA* 85mm for testing.
Just saying