I bought a competitor a 18X52mm to 16.59 betrayed my son. As you can see in the photo and comment left on the device if you do a search on Amazon. As I wanted one for myself, I took one with a 30x52mm zoom. Problem, the proposed 30x52mm comes here to 29.42, although the vendor says on the 30x52mm device has the same magnification as the 18x52mm and if we have no way to check, we have done and said nothing. I have compared with an optical shooting, a bezel 3-12x50mm and max magnification my glass is slightly larger than the 2 telescopes, so the two devices are less than the 12 magnification. For 18x50mm little move it to 17, but not for 30x50mm 30. I therefore requested reimbursement of the nonconforming product.