[B5536FTF-SB]55FL F3.6 Astrograph FTF-M57 Focuser Set (Sunrise Blue) Part # B5536FTF-SB Description 55FL F3.6 Astrograph FTF-M57 Focuser Set (Sunrise Blue) Aperture 55mm Fluorite Focal length 200mm F-ratio 3.6 Lens configuration 6 elements in 5 groups Coating Fully multi-coated Physical length 210mm Tube diameter 80mm Weight 1.2kg Filter 48mm (7880) & 52mm (7000) Parts included 2555, 55FL80B, 2 x 7026, 7051, FTF-M57, FTF-BORGII, 7880, 7352, 2 x 7085 & 2 x 7020 Notes FTF-M57 is 7901 version