SV135 7 mm to 21mm adjustable focal length; SV135 7-21mm zoom eyepiece equivalent to multiple eyepieces; obtain higher magnification with short focal length; It could bring you a better observation experience in a comfortable situation with high-contrast imaging. 18mm - 16.3mm comfortable eye relief; especially for eyeglass wearers ;designed primarily for viewing landscapes and astronomical observations of lunar surfaces; planets; nebulae; clusters; and diffuse nebulae. Fully multi-coated Premium eyepiece; The true fully multi-coated Premium eyepiece with superior edge and center sharpness than normal PLOSSL eyepieces; 6-Element 4-Group premium optical design for superior optical performance. Standard 1.25Inch eyepiece; Equipped with a precision-made standard 1.25-inch lens barrel that is compatible with any telescope that accepts 1.25-inch eyepieces; Rubber eye guard for comfortable viewing and blocking stray light. A cost-effective eyepiece; Full metal body; fine appearance; 40-57° wide angle field of view; high brightness observation is very comfortable; you will obtain more details that you have never seen before. Color:Black Material:Metal Package Contents: 1 * for SVBONY SV135 Zoom Eyepiece