The best performing Plossl eyepiece I have ever used or I would not be selling them!! These are simply put STERLING ! Manufactured using high grade lens, with 40 layers of fully multi-coated optics and 98% penetration. This advanced method of coatings yield super sharp, flat images from galaxies to planetary observing. These sharp looking Sterling Series Plossls are exceptionally baffled, with edge blackened lens, leaving virtually no ghosting or internal reflections. Unique design eliminates the need for rubber eye guards. Barrels are threaded to accept 1.25'' filters. Dust caps included to protect lens. **Classy, Sleek look adds to this already professionally made eyepiece. Focal length: 20.0mm Eye relief: 12.0mm Barrel size: 1.25 inches Field of view: 55.0 degrees Lens construction: four elements in two groups Construction: aluminum Coating: 40 layer fully multi-coating Weight: 97g STRLG20Regular price: $49.95Smart-Sale price: 888.291.6577 Located in Saint Augustine, FL 32095 By faith we understand that the universe was created by God's command, so that what is seen has been made from things that are not visible Copyright (R) 2019 SmartAstronomy, All rights reserved.