[6255]55FL Basic OTA Set Part # 6255 Description 55FL Basic OTA Set Aperture 55mm Fluorite Focal length 250mm F-ratio 4.5 Lens configuration 2 elements in 2 groups Coating Fully multi-coated Physical length 230mm Tube diameter 60mm Weight 0.5kg Filter 58mm (front hood) Parts included 2555, 7761, 7602, 7604, 7205 & 7000 Notes Needs a 2-inch holder for visual use