One of the most useful and overlooked pieces of terminal tackle for fishing the White River are tippet rings. These little rings come in three sizes (2mm, 2.5mm, & 3.1 mm) from Angler’s Image.
I do not think size matters much unless you are using them to sink midges just below the surface film then I usually use the largest size.
I mainly use them for depth control or more precisely so that you fish at a consistent depth. Much of our nymph and midge fishing is done with a strike indicator.
Once we find the proper depth (where the fish are) it is important that we continue to fish at that depth. I like to us a 3X leader with a large tippet ring tied on at the end. I then tie a foot or so of 5X to the ring and attach my fly or flies to that, put an appropriate amount of shot above the ring and set your indicator so that you are at the proper dept. As you change flies you will shorten the tippet until it needs replaced. Your shot rests on the tippet ring insuring a constant depth and that your shot doesn’t slip down.
The above is the most obvious use of tippet rings, however there are others. Midge fishing in the surface film can be improved by using the tippet ring as a tiny bit of weight so that your midge is just under the surface many times that will encourage strikes.
I also use them on larger dry flies as they can sink the tippet just below the surface which lowers the visibility of the leader.
I had to lose several before I learned to tie them on the leader before removing them from the swivel they come on _ Jim Dugan