The nitrogen-filled, IP67 waterproof, shock proof, fog proof Sightmark Rapid AR 5-20x40 SCR-308 Riflescope gets you on target with precision optical quality packed in an elite, compact body. Built specifically for modern sporting rifles chambered in .308 ammunition, with a rugged 6061-T6 30mm tube and scaled perfectly for lightweight, fast-action professional and competition shooting, the Rapid AR Riflescope boasts an SCR-308 finely etched reticle, complete with red-illumination and calibrated subtension lines for 150 gr. .308 Winchester bullet drop compensation. 10 Reticle illumination brightness settings provide the intensity for daylight to no-light shooting. The generous 4” eye relief provides shooters with a robust field of view while an advanced, fully multi-coated, scratch resistant lens system, 5-20x magnification and an easy-to-focus rapid power rotation eyepiece work together to give razor sharp, lightning quick target acquisition. Whether your rifle is all business, all competition or all fun, exposed pop-up locking turrets deliver precise ¼” per click windage and elevation adjustments for superb tracking. The Sightmark AR 5-20x40 SCR-308 Riflescope is the perfect mid- to long-range second-focal-plane-optic to make your mark.