This 2x barlow lens with metal body, the lens fully multi-coated provide a sharp view; it can double the power of any 1.25” telescope eyepiece, ideal for high power observation; a brass compression ring can protect your eyepiece from marring or scratching the barrel. The SVBONY super 1.25" 40 mm plossl eyepiece engineered with high quality 4 element design and offers a generous 40 degree apparent field of view perfect for broad field lunar observations;medium sized star clusters;provide a wide range of cloudy nebulas and deep sky targets 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 Lens edges are blackened to reduce scattering of stray light and maximize contrast.