25 inch (31.7mm) diameter eyepiece for astronomical telescopes. Eyepieces are suitable for astronomy professionals and beginners. Focal length: 10mm , you can freely observe objects with different distances and sizes. When the eye is close to the eyepiece, a soft cover is attached to the eyepiece so that the eye can comfortably touch the eyepiece while watching. Upgraded Lens has better imaging effect, chromatic aberration is balanced and corrected, and the image is clear.Eyepieces support all types of telescopes, reflectors and refractors. Observe the star clusters, moon, sky and planets in greater detail. The image plane is flat and chromatic aberration is corrected in a well-balanced manner, resulting in a clear image. The lens material is made of high-grade optical glass. Achieves a clear field of view and excellent contrast. Multi-coated Lens to provide a better sharp image. Color: As Shown Material: Metal+Mirror Specification: 10mm Package Contents: 1* telescope eyepiece Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.