http://www.tacscopes.com/product/58554 "They started by improving the optical configurations which lowered the F-stop factor and increased optical resolution. By doing this, more light travels through the lens to the tube. More light and better resolution simply means brighter and sharper image. Then we added our precision ""Red on Green"" aiming system, easy push button operation, reticle brightness adjustment and our detachable most powerful in the industry 450mw Infrared Illuminator with dedicated windage and elevation adjustments. Our ATN Aries MK 390 Weapon Sight is the best 1st Generation scope on the market. The ATN Aries MK 390 easily mounts onto any U.S. standard 7/8"" weaver or Picatinny rail. Features: - Powerful 4x multi-coated all glass optics - High resolution Gen 1+ Image intensifier tube - Easy to see ""Red on Green"" reticle system - Reticle brightness adjustment - Detachable Long Range infrared illuminator - Water and fog resistant - Limited two-year warranty - Included Accessories: Instruction manuel, lens cap, lens tissure, soft case (green), warranty card, two lithium batteries, IR450-B4 (Infrared Illuminator) Specifications: - Intensifer Tube: 1+ - Resolution: 40 lp/mm Center - Magnification: 4x - Lens system: F:1.4, F90mm - FOV: 10° - Range of focus: 4m to infinity - Controls: Direct - Windage & elevation adjustment step size: 1/8 inch to 100 yards adjustment - Reticle: Red On Green - Infra-red illuminator: 450mW Detachable - Battery life: 20 hours - Power supply: (1) 3v lithium (CR123A) - Enviromental rating: Weather resitant - Operating temperature: -40 to +50 C - Storage temp: -50 to +70 C - Diopter adjustment: +/-5 - Dimensions: 275 x 108 x 83.5 mm, 10.8” x 4.3” x 3.3” - Weight: 1.45 kg / 3.2 lbs"