***** **********Best Quality Guranteed. *****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 - 16.3 mm 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 1.25" 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 e