Orion Binocular Viewer for Telescopes With our Binocular Viewer, you'll swear you are seeing in three dimensions! Most observers perceive more detail in objects when gazing with two eyes instead of one Hinged aluminum housing contains fully multi-coated BAK-4 prisms for high light transmission Reflectors and short-focal length refractors may require a short 2x barlow lens Includes storage case and caps for eyepiece holders and barrel. Eyepieces sold separately