Details: You were born with two eyes, so why not use both of them when stargazing with a telescope? Now you can, and what a difference it makes. With our Binocular Viewer you ll swear you are seeing in three dimensions! The effect is most pronounced on the planets and Moon, but even deep-sky objects seem to have more clarity and depth. Most observers also perceive more detail in objects when gazing with two eyes instead of one. The hinged aluminum housing contains fully multi-coated BAK-4 prisms that provide high light transmission. You can use almost any matching pair of 1.25 eyepieces (sold separately), which are each held securely by three non-marring nylon thumbscrews. The Viewer s 1.25 barrel is threaded to accept filters. The Binocular Viewer works with all types of telescopes. Achieving focus with a reflector or short-focal length refractor, however, may require use of a short 2x barlow lens. Comes with foam-fitted aluminum case!