Product details:

Explore Scientific 3x Explore Scientific Focal Extender (with 2-inch Barrel) accepts both 1.25 inch and 2 inch eyepieces. It increases the magnification of your eyepieces, meaning that, for example, if you had 2 eyepieces, you now have 4! Best of all, your eyepieces maintain their original eye-relief when using the focal extender, making viewing more comfortable, especially for eyeglass wearers. All air-to-air lenses are fully EMD coated and all lens edges are blackened at the edge to maximize image contrast. Enjoy increased versatility when viewing.