The SVBONY SV131 1.25" Plossl 32mm Eyepiece uses premium optics that are fully multi-coated for crisp images. The folding eyecup lets you view with or without glasses, works well for views of the moon, planets, deep-sky objects and terrestrial observations. It's a great birthday christmas gift. 1.25" Plossl eyepiece is suitable for any 1.25" telescope barlow lens and filter;also supports the installation of other 1.25 inches accessories.Thread size is M28.5*0.6mm,can supports standard 1.25-inch filter adapter installation. with 19mm exit pupil distance, it is convenient for you to observe for a long time. The 1.25 inches Plossl eyepiece is suitable for observing nebulae, star clusters, comets and other low-light, dim celestial bodies. 1.25in Diagonal fits telescopes with 1.25in focusers. Accepts standard 1.25” eyepieces, filters, Barlow lenses and other accessories with a 1.25in insert barrel. The SV221 main mirror shell is made of precision molded ABS plastic, and the lens barrels at both ends are precision machined from aluminum, which will not be easily damaged. The SV221 diagonal mirror has M28.5x0.6mm thread, standard thread size, you can install 1.25 inch filter. Use the SV221 zenith mirror to obtain an upright image and an upside-down image. With a brass pressure ring. The SV221 diagonal mirror can protect the eyepiece from being scratched and not damage the service life of the eyepiece.