This Small Compression Ring Set from Novagrade includes four compression rings and permits any Novagrade digiscoping adapter to be used with 23mm to 40mm-diameter eyepieces. Such eyepieces may be found on microscopes, small telescopes, and binoculars.

Installation is easy: simply remove the adapter's retaining ring, swap out the original compression ring with the right one from this set, and replace the retaining ring. The compression rings each feature an expandable design, constructed from an injection-molded plastic polymer and made in the USA.