Burris XTR II 3X-15X-50mm Illuminated FFP G2B Mil-Dot Reticle Riflescope - 201033 Designed for serious, technical, long-range precision rifle shootersboth tactical and competitive Front focal plane reticle design allows the reticle size to increase or decrease as magnification is increased or decreased; trajectory compensation is always correct and proportional for the selected power setting; also called first focal plane or FFP Ergonomic side focus and easy-to-reach parallax adjustment from 50 yds. to infinity for improved accuracy at long distances Excellent resolution optics and tactical-appropriate reticles and adjustment knobs make it easier to identify targets and adjust for windage and elevation Illuminated reticle reduces time to get on target in any lighting condition and dramatically increases accuracy when target is dark. Main Tube Size: 34mm