1.25″ and 2″ UHC, O-III, H-Beta, Moon & Skyglow, IR/UV-Cut Filters View cart “Kson O-III (Oxygen 3) Filter (Light Pollution) 2″ Telescope Eyepiece Filter” has been added to your cart. View: 12 24 All Achromat + Semi APO (22) Narrowband (21) UHC/O-III (7) Visual, Moon, Neutral Density (31)