1. For Super Wide Angle 1.25Inch 7.2mm-21.6mm Zoom Eyepiece allows you to change the magnification without changing the eyepiece. 2. / 4 groups made of high refractive index glass provide clear, high-contrast distant views. 3. Blackened lens edges and anti-reflective lines for maximum contrast. 4. Extra-long 18mm-20mm eye relief range allows the use of glasses without reducing of view visible through the eyepiece. Model: SV191 Length: 7.2-21.6mm Eye Relief: 18-20mm Field of View: 42°-65° Field Stop Diameter: 16mm Tube Size: 1.25inch Filter Thread Standard: .5*0.6 Coating: Full Multi-Coating Blackened Lens Edges: Yes Eyecups: Screw-Up Colour:Black Material:Metal Package Contents: 1 * Telescope Eyepiece Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.