A good barlow needs good optics, but good optics alone arent enough. Unlike many barlows, ours are internally baffled, rather than simply painted black inside, to block transmission of off-axis light. This baffling results in noticeably higher contrast when observing faint objects that are near bright stars or other sources of glare. It also helps reduce glare during daytime terrestrial observation. Each has a multi-coated, two-element achromatic lens which doubles the power of any eyepiece. Black-anodized aluminum body with eyepiece setscrew. Made in Japan.