Many introductory telescopes sold worldwide use a smaller, older 0.965" diameter format for diagonals, eyepieces, and other accessories. Having a 0.965" barrel severely limits the number of eyepieces and accessories you can buy and use in the after-market. This popular eyepiece adapter allows 1.25" eyepieces, diagonals, and other accessories to be used in 0.965" focusers, and at once allows hundreds of more common 1.25" format astronomy items to be used with your telescope.
Precision machined from black anodized aluminum, this premium adapter includes a brass compression ring that restrains the eyepiece and prevents marring of the eyepiece barrel by the metal set-screw. Total height = 1.74" (44.2mm). Height of upper 1.25" barrel = 1.04" (26.4mm). Height of lower 0.965" barrel = 0.7" (17.8mm). Weight = 1.4oz.
Please note that the use of extension/conversion tubes such as this item requires additional in-focus travel. If your eyepiece is fully seated in the 1.25" upper barrel, then you will require 1.04" of additional in-focus travel. If your eyepiece does not fully seat in the barrel and extends out, then you will require additional in-focus travel by the amount the eyepiece extends out. As in the case of barlows, focal reducers, diagonals, and other accessories, your telescope may or may not be able to accommodate this additional travel requirement, so you may not be able to reach focus with all eyepieces and configurations. That is technically a limitation of the mechanical design of the telescope and not a shortcoming of the product itself.