Vixen's new SSW 5 mm Ultra Wide 1/25" ED Eyepieces feature an exceptional 83° wide field of view. Its 7 element design, features high-transmission/low dispersion lanthanum and exotic glass. This combination offers unparalleled contrast and sharpness, outclassing all current brands. Full multi-coating on all lens surfaces, in combination with special coating on the lens connecting surfaces, delivers high contrast sharp star images across the entire field of view. No edge darkening or vignetting is evident over the viewing surface, even with fast f/4.0 optics. The advanced multi coating on each lens surface offer high light transmission, over 99.5%, throughout the visible rays of light (430nm - 690nm) and produce extremely bright and clear images.