Orion 13039 2-Inch Crayford-Style Telescope Focuser Smooth, accurate Crayford-style focuser for reflector telescopes accepts both 2" and 1.25" eyepieces Focuser body is contoured to fit 8"-12" reflector telescope tubes Roller-bearing design provides zero image-shift through focusing range - significantly improves performance compared to rack and pinion focusers Features deluxe machined focus knobs with rubber grips and adjustable tension control Lets you easily achieve the sharpest possible focus through a telescope, even at high magnifications