Item Type: Telescope Eyepiece_x000D_ Material: Aluminum Alloy, Optical Glass_x000D_ Weight: Approx. 57g / 2oz_x000D_ Focal Length: 4mm / 0.2in 1Size: Standard 1.25 inch/31.7mm universal eyepiece for astronomical telescopes. 1.25 inch 4mm eyepiece gives the widest viewing field along with extra sharpness. 2Telescope Eyepiece: 4mm focal length eyepiece for wide field of view and superior performance. Foldable eyecup allows for comfortable viewing, even with glasses. 3Fully Coated: Offers bright and sharp images with excellent color correction for planetary viewing and daytime observation. Fully coating group on each lens surface maximize light transmission, contrast and gets clear images 4Features: All metal construction with a threaded bottom for 1.25in filters, compatible with standard 1.25 inch interface telescopes or filters. 5Widely Used: Suitable for all astronomical telescopes with a 31.7mm interface. Perfect for broad field lunar observations, medium sized star clusters, and a wide range of cloudy nebulas and deep sky targets. 1 xTelescopeEyepiece 1 x Storage Box