1、The product is made of high quality aluminum alloy, can be used for any 1.25 inch astronomical telescope and concentrator. 2、For lens with the same refractive index, 62° aspheric eyepiece are more thin and light than spheric eyepiece, and are mainly used for planetary observation. 3、The wide angle 62° aspheric eyepiece can obtain the maximum detail and clarity in the entire field of view, and obtain almost distortion free images. 4、This eyepiece provides high magnification, looks closer and more detailed, for viewing the moon and planets. 5、With anti loss design, the groove part of the eyepiece interface can prevent loss, suitable for viewing scenery, bright celestial bodies, nebulae, etc. Item Type: Aspheric Eyepiece Material: Aluminum alloy Application: HD full coated telescope accessory Type 4mm 62° Aspheric Eyepiece 1.25in 10mm 62° Aspheric Eyepiece 1.25in 23mm 62° Aspheric Eyepiece 1.25in Focal Length 4mm / 0.16in 10mm / 0.39in 23mm / 0.91in Vision 62° 62° 62° Fitting Diameter Standard 1.25in / 31.75mm Standard 1.25in / 31.75mm Standard 1.25in / 31.75mm Lens Diameter 0.39in / 10mm 0.39in / 10mm 0.87in / 22mm Coating Optical Lens, Fully Coated High Definition Optical Lens, Fully Coated High Definition Optical Lens, Fully Coated High Definition The Structure of The Optical System Aspheric Eyepiece Aspheric Eyepiece Aspheric Eyepiece 1 x Aspheric Eyepiece 2 x Lens Protection Dust Cover