Orion 8921 9mm Expanse Telescope Eyepiece 9mm 1.25" telescope eyepiece offers a wide field of view and superior optical performance at a bargain price Nice 15mm eye relief lets eyeglass wearers view the entire field without removing their glasses Wide 66 degrees apparent field of view lets you see more of the sky Delivers sharp images with good color correction and contrast Aluminum 1.25" eyepiece barrel is internally blackened to eliminate light scattering, and is threaded to accept 1.25" Orion filters