[107F6FTF]107FL F6 Astrograph Set (FTF-M57 Focuser) Part # 107F6FTF Description 107FL F6 Astrograph Set (FTF-M57 Focuser) Aperture 107mm Fluorite Focal length 650mm F-ratio 6.0 Lens configuration 4 elements in 3 groups Coating Fully multi-coated Physical length 526mm Tube diameter 80mm Weight 2.9kg (OTA only) Filter 82mm (front cap) Parts included 2107, 7803, FTF-BORGII, FTF-M57(7901 version), 7352, 7108 & 2 x 7085 Notes The back end of FTF-M57 is 7901. A set includes a pair of mounting rings.