7-21mm Zoom eyepiece Feature: 1.Fully multi-coated Premium eyepiece zooms to any focal length between 7 mm and 21mm 2.Zoom from low to high power in an instant with this versatile eyepiece 3.Compatible with any telescope that accepts 1.25 eyepieces 4.6 -Element 4-Group premium optical design 5.Comfortable 18mm - 16.3mm eye relief more comfortable, especially for eyeglass wearers Technical parameters: 1.Brand: SVBONY 2.Model: SV135 3.Focal length: 7-21mm 4.Zoon Type: Linear 5.Lens structure: 6PCS / 4group 6.Eye Relief: 18mm - 16.3mm 7.Interpupillary Dist.:15mm 8.Barrel Size: 1.25 9.Field of view: 57~40 10.Coatings: Fully Multi-Coated-Green 11.Rubber Eye Guard: Yes 12.Meterial: Metal 13.Color: Black 14.Thread Size: M28.5*0.6 15.Overall length: 93mm Net Weight: 133g / 4.67oz Package Include: 1XSVBONY SV135 7-21mm 1.25 inch Eyepiece 1XLens Covers (Objective and Eyepiece) 1XLens Cleaning Cloth 8mm-24mm zoom eyepiece Features: 1.SVBONY Super-wide Angle 1.25 8mm-24mm zoom eyepiece. 2.The zoom eyepiece allows you to change magnification power without swapping out eyepieces. 3.7-Elements / 4-groups made of high index glass deliver sharp, high contrast vistas. 4.A simple twist of the zoom eyepiece housing changes the focal length from 24mm to 8mm, providing a variety of viewing magnification powers. 5.Exceptionally long 18mm-19.5mm eye relief range allows eyeglass wearers to enjoy the entire field of view without needing to remove their glasses. 6.Sleek black barrel with safety undercut to reduce the possibility of the eyepiece slipping out of the focuser or diagonal. 7.Blackened lens edges, anti-reflection threads for maximum contrast. Specification: 1.Brand: SVBONY 2.Model: SV171 3.Focal Length: 8-24mm 4.Eye Relief: 18-19.5mm 5.Apparent Field of View: 38-56 6.Barrel Size: 1.25inch 7.Lens Structure: 7-Elements/4-Groups 8.Filter Threads Standard: 1.25 Filter Thread (M28.5 x 0.6) 9.Coatings: Fully Multi-Coated 10.Blackened Lens Edges: Yes 11.Barrel Safety Recess: Yes 12.Eyecups: Twist-Up 13.Eyecups Material: Metal Net Weight: 300g / 10.58oz / 0.66lb Package Includes: 1XSV171 Black 1.25in 8-24mm Zoom Eyepiece 1XTwo Rubber Dust Cover 1XMirror Cloth SVBONY SV171 Zoom Eyepiece 8mm-24mm review