About the configuration: the focal length is 900mm, the aperture dia is 60mm, with 3 eyepieces: SR4 (for daytime viewing), H20 (for moon at night) and H12.5 (see other celestial bodies). In addition, it is equipped with a 3x Barlow lense and a 1.5x erecting eye piece . About multiples: separate eyepieces: SR4mm, H12.5mm, multiples of H20mm are: 900/4=225 times, 900/12.5=72 times, 900/20=45 times. Together with the 1.5x positive mirror, the imaging is a positive image, and the multiples are: 338 times, 108 times, 67.5 times. If you do not install a 1.5x mirror, but a 3x Barlow lense, the multiples are: 675 times, 216 times, 135 times. In other words, if we choose the eyepiece SR4mm, and then match the 3 times Barlow lense, then we can set up 675 times. Namely: magnification: 45 times - 675 times. Note: 3 eyepieces (SR4mm, H12.5mm, H20mm) can only be selected for one installation at a time, and 2 multipliers (3x Barlow lense erecting eye piece) can only be selected at the same time.