The XW 20 eyepiece is designed for use with a wide range of PENTAX spotting scopes and telescopes. Ideal for both ground and astronomical observations, this eyepiece features fully multi-coated lenses to increase light transmission and color quality, high-refraction lanthanum glass elements for high-resolution images with minimal aberrations, and JIS Class 4 weatherproof construction for durability. Engineered using advanced computer simulation design technology, this high-performance eyepiece provides a 70 degree field of view and 20mm eye relief.