Please note: This text was taken directly from the manufacturer.
With a wide 43-deg apparent field, Orion's Sirius Plossl line of telescope eyepieces provide clear, sharp images of impressively high contrast. They're suitable for all telescope types: reflector, refractor, and catadioptric. Each 4-element Sirius Plossl eyepiece is fully coated with magnesium fluoride on every air-to-glass surface. Lens edges are blackened to reduce scattering of stray light and maximize contrast. Lenses are mounted in black anodized aluminum housings with 1.25" chrome-plated brass barrels. Each eyepiece is fitted with rubber eyeguards and internally threaded to accept standard filters.
