Celestron 93398 Axiom LX Series 2 Inch 23 Retractable eyecups - Ultra-low profile for eyeglass wearers Parfocal eyepiece - Little or no focusing is needed when changing from low to high power Threaded barrels - Accepts 2" thread-in filters Polished and hard anodized aluminum barrel - Scratch resistant and high-end appearance Rubber gripping ring - For secure handling and smooth control of eyecup