Our Pyrex (made of the same high-quality, durable glass as the baking dishes in our kitchens) glass bottle slides are perfect for resonator dulcimers. Exceedingly smooth surface, no noise as they slide across your resonator dulcimer strings, and rounded ends so you don't scrape your fingers (or your dulcimer!).
We carry the Dunlop resonator slides in three sizes. The size is the inside diameter of the tube, and which size you choose depends on your finger size, and on which finger you use to hold the slide.
This resonator dulcimer slide (also used for other instruments, of course!) is Dunlop's "No. 213", which has a length of 69 millimeters, a wall thickness of 4.5 millimeters, and an inside diameter of 23 millimeters.
Dunlop says that this slide, #213, fits a ring size of 13 1/2.
