GSO PREMIUM 20mm PLOSSL Eyepiece 1.25″ 4-element design is renowned for its outstanding performance. Superior Multi-Coated (FMC) With 52 Degree Field Of View allowing increase clarity, sharpness and clean impressively high contrast images, utilisation of top quality glass. They’re ideal for all types of telescopes: reflector, refractor, and catadioptric such as Maksutov-Cassegrains and Schmidt-Cassegrains.