Athlon Optics , Talos , Riflescope , 4-16 x 40 Second Focal Plane (SFP) 1" Tube, Illuminated BDC 600 Reticle , 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 Heat treated one piece tube gives the scope extra strength over multi-piece tubes. A one piece tube also is better at keeping moisture out thus keeping your scope fog proof for the life of the product Nitrogen purging dramatically reduces the moisture inside the tube and helps maintaining Fog proof and waterproof 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