Really not sure if this is the common name for these little gems but I can tell you, making them nearly “tipped” me over the edge…I etched some copper tube and then cut it into segments, cut out and domed caps to fit-then proceeded to put it all together–soldering teeny, tiny parts…like real teeny.  After more than a dozen attempts, here is what I have to show for it all–

And am lovin’ the results…just not sure the effort required is something I will do again–it was a LOT of work!!!  Also did a few 10 ga. copper textured rings-soooo much easier than the tubes!  Now I am off to find a terrific project to use them in!