Features: Designed primarily for planetary observation and deep sky objects Exceptional at nearly eliminating lateral color aberration and light scatter while retaining excellent sharpness, contrast and definition Fully multi-coated green lenses for excellent image contrast and light transmission Wide 58 degree field of view, fold-down rubber eyecup Standard 1.25" fitting diameter to the scope's eyepiece holder Standard 1.25" inner thread to fit light filters Comes with lens caps for both ends Focal length: 4mm Large eye lens diameter: 21mm Comfortable long eye relief: 15mm Net Weight: 160g Package Includes: 1xSWA 1.25" 4MM 58-Degree Planetary Eyepiece Package List 1Designed primarily for planetary observation and deep sky objects 2Exceptional at nearly eliminating lateral color aberration and light scatter while retaining excellent sharpness, contrast and definition 3Fully multi-coated green lenses for excellent image contrast and light transmission 4Wide 58 degree field of view, fold-down rubber eyecup 5Standard 1.25" fitting diameter to the scope's eyepiece holder