Twist-Up eyecups SV191 7.2-21.6mm zoom eyepiece can meet the needs of most people; including the needs of users who wear glasses. Fully Multi-coated lens SV191 zoom lens optic design increases light transmission, delivers bright, clear, high-contrast images even in low-light conditions. 42°-65° Apparent Field of View SV191 7.2-21.6mm zoom eyepiece allows you to see different wide field of view under the same viewing conditions. Meet your different needs. Blackened Lens Edge Lens edges is blackened to reduce scattering of stray light and maximize contrast; designed to enhance the functionality and pleasure of using your telescope. 2 rubber dust covers Keep your eyepiece lens away from the influence of dust and extend its service life. Specification: Focal Length: 7.2-21.6mm Eye Relief: 18-20mm Apparent Field of View: 42°-65° Field stop diameter: 16mm Barrel Size: 1.25" Lens Structure: 7-Elements/4-Groups Filter Threads Standard: M28.5*0.6 Coatings: Fully Multi-Coated Blackened Lens Edges: Yes Eyecups: Twist-Up Eyecups Material: Metal Net Weight: 167g / 5.87oz / 0.367lb Package Includes: 1X Black 1.25" Zoom Eyepiece 7.2-21.6mm 2X Rubber Dust Cover 1X Mirror Cloth.