With unsurpassed optical clarity and offering a 70 degree field of view for comfortable viewing, PENTAX offers a wide selection of focal lengths with the XW eyepieces. They feature 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 eyepieces also offer an unsurpassed 20mm of eye relief. Designed for use with a wide range of telescopes and PENTAX brand spotting scopes, the XW series eyepieces are a clear choice for ground and astronomical applications.Description 70 degree field of view for easier viewingFully multi-coated lenses increase light transmission and color qualityAdvanced computer simulation design technology was used to drastically reduce internal reflections producing brighter, clearer imagesDesigned specifically provide ideal viewing conditions when used with a telescopeHigh-refraction, low-dispersion lanthanum glass elements deliver bright, high-resolution images with minimal aberrations and distortionJIS Class 4 weather proof construction makes these eyepieces more durableSpecifications Eye Relief: 20mmEypiece Ring: Helicoid TypeWeight: 14.3 oz. (405g)What"s in the box: Lens CapTube Cap