SVBONY 25mm telescope lenses 4-element plossl design for astronomy telescope; fully multi coated broadband green film optical glass and approx 40 degree filed of view for broad field lunar observations 4 element broadband green film optical glass: Premium symmetrical Plossl optical glass lens gets excellent aberration correction and extremely high resolution rivaling 25mm eyepiece with standard 1.25”interface: M28.5x0.6mm filter threads fits for any standard 1.25" telescope eyepiece filters or devices to the moon or celestial bodies 40 degree apparent field of view: Broad-field lunar observations of the Moon;planets;medium-sized star clusters;cloudy nebulas Blackened lens edges and blackened interior: The inside of the adapter is fully threaded to minimize reflections to reduce scattering of stray light and maximize contrast Foldable rubber eye guard are easier and more comfortable, especially for eyeglass wearers,No slip, rubber grip ring for secure handling, even in moist conditions The SVBONY super 1.25" 40 mm plossl eyepiece engineered with 4 element design and offers a generous 40 degree apparent field of view Detachable eyepiece The length of the eyepiece can be changed by disassembly Removable rubber eye guard for those wearing glasses and glasses The built in rubber eye guard enhances viewing by helping to block out ambient light and position no introduction of additional color for higher magnification;highly achromatic;enhance the details of planetary filters.It can be removed for eyeglass wears and astronomy photography. M28.5x0.6 filters threads,features a precision made standard 1.25" barrel for any 1.25'' astronomy filters