See the whole picture with Ultima Edge. These flat-field eyepieces were designed to provide an ultra-sharp, ultra-clear, crisp image from the center all the way to the edge of the field of view. The 15mm Ultima Edge eyepiece features fully multi-coated optics and an 8- element lens design, maximizing light transmission.The Ultima Edge 15mm has a generous 65 field of view perfect for viewing planets, stars and the Moons surface. This eyepiece provides higher-powered magnification, perfect for those times when you want to get up close to smaller objects.BodyThe 15mm Ultima Edge eyepieces main housing is machined from high grade aluminum with a black anodized outer surface. Its 1.25" mounting barrel is internally threaded to accept threaded to accept standard 1.25" filters and adapters. It is compatible with 1.25 star diagonals and focusers. On the exterior of the eyepiece, you will find a uniquely designed, molded rubber grip ring for non-slip handling during observing sessions.Viewing through the 15mm Ultima Edge eyepiece is comfortable for both eyeglass wearers and non-eyeglass wearers alike, thanks to the rubber eyecups and long eye relief of 16mm.Convenient Parfocal DesignSpend more time observing and less time focusing! When you buy more than one Ultima Edge eyepiece, you can switch between them without refocusing thanks to their parfocal design. With a set of Ultima Edge eyepieces in your kit, you'll be able to enjoy a wide range of high and low power viewsand switch between them quickly and easily. That means you can get more out of every observing session. NOTE: Ultima Edge 24mm is not a parfocal eyepiece. Ultima Edge eyepieces are only parfocal within the line and do not maintain focus when swapped with parfocal eyepieces from other brands or series.