This SV152 20mm premium 1.25" wide angle eyepiece includes an illuminated Single crosshair reticle that greatly simplifies centering celestial objects in the eyepiece for more accurate go-to alignment and tracking; An invaluable aid to centering guide stars and astrophotography target objects. It is the field of view that matter. Wide 70-degree apparent field of the sky allowing you to find objects and alignment stars more easily than shorter focal length eyepieces ;Comfortable 16mm eye relief; lets you easily find and locate target objects. There are also other uses for the SV152 crosshair eyepiece; The lighting part of the product is removable;with it you can use it as an illumination eyepiece.;remove it and you can use it as ordinary eyepiece. The SV224 dovetail base is suitable for most kind of telescopes and has strong compatibility. The dovetail base includes two large screws which are fit into the recessed slotted mounting holes. Precision machined dovetail base, made of high strength aluminum with anodizing aluminium process, durable for long time use. The aluminum material makes the product lighter and easier to carry. The dovetail base is compatible with most finderscopes, like SV182, SV106.