Genuine Brass Rings (from India). We know that you kaleidoscope users often need brass check rings, so we had a bunch made in different sizes. One set of rings has a 3/8 inch hole which would be for the viewing end of the kaleidoscope; the other rings are totally open except for about 1/8 around the edge. There is also a lip around the bottom of each piece.
Here's a picture (click for larger image) from the top of the two different types; the 'open' ring and the 'viewing' ring (with the 3/8 inch hole)
