Athlon Optics , Midas BTR , Riflescope , 4.5-27 x 50 Second Focal Plane (SFP) 30 mm Tube, Illuminated APMR1 MIL Reticle , HD Glass gives you the utmost contrast, light transmission, and the sharpest image. Advanced Fully Multi-Coated lenses gives you better light transmission to bring optimum brightness and true color across the entire light spectrum. Reticle etched on the glass that provides excellent backing support for complex reticle design and offers great durability and much higher shock resistance to recoil Argon purging gives you better waterproofing and thermal stability The 6061T6 aircraft grade aluminum tube that has exceptional strength and superior mechanical integrity will protect these world class optics no matter what punishment you throw at it