Orion HighLight Plossls, an exclusive, premium line of 1.25" Plossl with some noteworthy enhancements. HighLight eyepieces offer a generous 50 degree field of view (43 degrees for the 40mm) and crisp, sharp images. But the HighLights' 4-element optics are not just fully coated or multi-coated, but fully multi-coated. That means that every air-to-glass lens surface is multi-layer coated for the highest possible light transmission and better contrast. You'll see more of those pinpoint star images and more faint detail in deep-sky objects. In addition, the lens edges are blackened for additional contrast enhancement. The machined aluminum housings of the HighLight Plossls sport a distinctive anodized finish, with grip traction knurled right into the metal. The supple rubber eyeguards shield out extraneous light and fold down for eyeglass wearers. They are internally threaded to accept filters. Each HighLight Plossl eyepiece comes with top and bottom end caps for protection against dirt.Highlight Plossl Expansion SetIf you already have the Starter Set, or the 25mm and 10mm eyepieces included with many telescopes, this set provides three complementary focal lengths for medium and high magnifications: 20mm, 12.5mm, and 7.5mm.