Equipped with eyepieces: H6mm, H20mm The multiples are: 300/6 = 50 times, 300/20 = 15 times. If you choose a 3 times Ballov lens, the magnification is 50X3 = 150 times, 15X3 = 45 times; plus a 1.5 times orthographic lens, the imaging is a positive image, and the magnifications are: 50X1.5 = 75 times, 15X1. 5 = 22.5 times. Namely: minimum magnification: 15 times, maximum magnification: 150 times.