Signature rings also accept Pos-Align Offset Inserts so you can virtually sight-in your gun without moving the scope adjustments. Lens systems perform at their optimum when all lenses are optically centered. By keeping the internal optics centered, you'll see through the scope all of the clarity, sharpness, and brightness that the optics designers intended for you to see. The offset inserts also correct for any mis-alignment caused by receiver holes drilled off center, or the bases or rings being slightly off of perfect center. For you extreme range shooters, the need for expensive tapered bases or shimming becomes a hassle and expense of the past. - 1".