1.25inch Orion Telescope Eyepiece Parfocal Rings, Set of Four This set of 4 Orion Parfocal Rings lets you make a set of non-parfocal 1.25" telescope eyepieces parfocal for more efficient observing Eliminate the need to make focus adjustments when changing telescope eyepieces Each black anodized aluminum parfocal ring features three equidistant setscrews for secure attachment to any 1.25" telescope eyepiece barrel With parfocal ring equipped telescope eyepieces you can change magnifications quickly and easily Also useful for setting focus point of calibration eyepiece used for focusing an imaging or guide camera