For comparison, I used lenses from Nikon, Leica, Vortex, Zeiss, and a few others. For the price, these eyeglasses were as excellent as or better than more costly models.At our ranch home, I've been able to see up to a distance of about a mile from my window. To a structure on the other side of a valley. I was astounded. However, the BDC must have open architectural in order to accommodate hand loading. In other words, this isn't a pre-packaged meal. To acquire a trajectory and holdover, I'll need to input the BC speed and the grain of the bullet.However, I want open architecture for my stock, so I'll stick with a kickass card. However, at the price, I'd purchase them again.