Main features: 2. It has autofocus throughout the entire zoom range. When changing the magnification, there is almost no need to refocus. 3. The wide focal length range allows for use on many instruments, whether it be compact APO, DOB, or fast Newtonian telescopes. 4. Nine elements (including non spherical surfaces), multilayer coated optical elements with excellent clarity, contrast, and color correction. 5. The zoom action is smooth, with stop devices at 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 24 millimeters. The field of view at 8mm is 72 degrees wide, and at 20mm it is 57 degrees wide. 8. Includes 1.25-inch and 2-inch lens barrels with threads and filter options. 9. More than 2x zoom ratio wideangle zoom eyepiece Specifications: 1. Brand: SVBONY 2. Model: SV230 3. Focal length: 8mm-20mm 4. Field of view: 57 ° -72 ° 5. Tube size: 1.25 inches and 2 inches 6. Coating: Full multilayer coating 7. Black lens edge: Yes 8. Exit pupil distance: 17-19mm 9. Qi Jiao: Yes 10. Rubber goggles: Yes 12. Non spherical eyepiece: Yes 13. Flat field design: Yes 14. Installation of astigmatism corrector: Yes 15. Tube Material: Stainless Steel 16. Filter thread: M28.5x0.6 and M48x0.75 17. Number of groups/components: 6/9 18. Outer diameter: 60mm 19. Height: 132mm 20. Net weight: 500g/17.66oz Packaging includes: SVBONY  8- 20mmeyepiece Eyepiece pouch 3PCS dust cover