SVBONY 12.5mm illuminated eyepiece features double crossline reticle; for accurate polar positioning and long-exposure photo-guiding when using with off-axis guiders for centering and guiding of stars. Double crosshair design, can easily align the target object. Helps locate and center stars well;also fits for guiding astrophotos when used in off-axis guiders or guide scopes; Notice deviation of the positioning easily;so that guide star and reticle appear in ideal sharpness and definition. Adjustable red LED light brightness control to illuminate crosshairs and preserve night vision, you can twist the knob to meet your different requirement. This versatile 50mm aperture guide scope with a built-in helical focuser for precise focusing of potential guide stars.Designed for use with the guider CCD astronomy camera or eyepiece. It is an ideal accessories to any astrophotographers. Extinction design of telescope. Taper matt tooth and spray matting paint design can greatly reduce the light loss of light in the entire lens barrel, making the image clearer and sharper; Unique design with double protection to avoid loss of light, making the images you observe clearer and sharper. 604g and 240mm total length that is very small and compact autoguiding system adds hardly any weight to an astrophotography setup.