Item Type: Astronomical Telescope Eyepiece Material: Aluminum alloy and optical glass Gross Weight: 125g/4.4oz Focal Length: 6mm/0.24in Field of View: 66 degrees Lens Coating: FMC green film Number of Lenses: 5 elements in 3 groups Connector Size: 1.25 inches(31.7mm) Anti Slip Design: Yes Thread Specification: M28.6x0.6mm                     .wang-edit-text{                         font-family:'Arial' !important;                     }                     .wang-edit-text table {                         border-top: 1px solid #000;                         border-left: 1px solid #000;                     }                     .wang-edit-text table td,                     .wang-edit-text table th {                         border-bottom: 1px solid #000;                         border-right: 1px solid #000;                         padding: 3px 5px;                     }                     .wang-edit-text table th {                         text-align: center;                 }1、6mm Focal Length: This lens has 6mm focal length, 25in joint diameter, which is suitable for 25in astronomical telescope. 2、66 Degree Wide Angle: This astronomical telescope wide angle eyepiece has a 66 degree field of view, 5 elements in 3 groups. 3、Optical Glass Lens: The lens adopts multi layer high definition broadband green film optical glass lens, chromaticity adjustment, which provides high permeability to ensure clear and has clear scenery. 4、Fully Coated Glass: The fully coated glass with excellent image contrast and light transmission with high brightness, large field of view that can keep your eyes in a comfortable state. 5、Applicable Scene: The lens is suitable for viewing scenery, bright celestial observation, nebula, etc., and it is also Halloween birthday Christmas gift for family and friends.