0.965"/24.5mm Astronomy Telescope Refractor Erecting Prism 45 Degree + Eyepiece Lens SR4mm 35 Degree Field of View. Fully Multi-coated: optical glass for maximum brightness and clear image. High Refractivity: high-definition prism, more comfortable viewing position. Eyepiece: suitable for telescopes, reflector, refractor, to observe the moon, nebula, deep sky, star and other planets. Just insert into the telescope, and then fix the eyepiece by the screw. Specification: Prism Material: Optical Glass + Plastic Eyepiece Material: Optical Glass + Metal Prism Size: 80mm/3.15inch Eyepiece Size: 3.7x2.8 cm/1.46x1.10 inch Eyepiece Focal Length: 4 mm/0.15 inch Interface: 0.965"/24.5mm Package Includes: 1x Telescope Diagonal Prism 1x Telescope Eyepiece