Sensei 72-95mm Aluminum Step-Up Ring

The Sensei 72-95mm Aluminum Step-Up Ring allows you to connect a lens with a 72mm front thread to a 95mm thread adapter ring. Unfortunately, you cannot replace the adapter ring for the matte boxes with a step-up ring because they are designed as a proprietary system.

Yes, you can stack 2 filters with the same size thread but beware of vignetting (darkening of the edges) with wider angle lenses.

They are about 5mm thick which is about the same as a standard UV filter ring.

Yes, the black color and finish covers the entire step up ring.

The Sensei 67-95mm Aluminum Step-Up Ring has course 1.0 pitch threading on the 95mm side, and standard 0.75 pitch on the 67mm side. This is fairly standard for these sizes.

If your filter/attachment is larger than your lens, it's a step-up. In this case, your fisheye attachment is 37mm and your lens' front diameter is 30mm, hence, you'd need a step-up ring.

Yes, it's meant for any circular filters with 82mm diameter.

This Sensei 67-77mm Aluminum Step-Up Ring would be used to connect a 77mm accessory to a lens with a 67mm thread.