This high quality 2.25X Barlow made from exotic lenses offers a rare 2.25X magnification factor, so you can get a higher magnification than with standard 2X lenses. The optics are covered with High Transmission Multi-Coated (HT-MC) layers. The lens has an eyepiece clamping ring which, unlike the standard screw mount, does not scratch the eyepiece sleeve. The Q-Barlow lens enables two magnification: 1.3x and 2.25x. The change is done by mounting an additional element, which can be found in the set with the lens. Stock Standard: 1.25 "(31.7mm)