The 32mm low power Omni eyepiece is a 4 -element premium symmetrical Plössl optical design. Features include blackened lens edges to minimize internal reflection and maximize contrast, multi-layer coating group on each lens surface to maximize light transmission and contrast, and each Omni goes through a two-step anodizing process to prevent reflection from the top eyepiece barrel, unlike most other manufactures who use reflective surfaces. Threaded barrels accept 1-1/4" Celestron thread-in filters.