The HDS uses cutting-edge Digital electronics design. Twenty brightness levels ensure proper brightness keep watch over in either low light or very bright sunlight. An on-board microprocessor provides automatic battery check indicator, up/down brightness scrolling and programmable auto shutdown features. All electronics are fully encapsulated in shock absorbing resin compound.OperationOptics: Transmission holography – 100% parallax freeMagnification: 1x unlimited eye reliefTemperature:-20 to 150F (operating); -40 to 160F (storage)Sealing: Waterproof (submersible) & fogproofColor/Finish: Non-reflective black with hard coat finishAdjustment (per click): 0.5-Inch at 100 yardsAdjustment Range: +/- 40 MOA travelMount: 1-Inch Weaver dovetail/Picatinny rail (Mil spec 1913)Return to Zero: Repeatable to 1 MOA after remountingHeads-Up Display Window Optical Surfaces: Anti-glare and scratch resistant coatingsWindow Dimensions: 1.20-Inch x 0.85-Inch (30 x 23 mm)Window Material: Shatterproof laminate (3/16-Inch thick)Field of view (100 yards): 30 yards (28m) at a 4-Inch eye reliefStandard Reticle: 65MOA ring with quadrant ticks with a 1MOA Aiming dotReticle Contrast Ratio: 28,000:1 brightest to lowestNight Vision CompatibleElectrical Power Source: 2 x -InchN-Inch alkaline batteries (available anywhere)Battery Life: 70 hours at nominal setting 12 (AA batteries: 350 hrs)Brightness Settings: 20 settings with scrolling featureAuto Battery Check Indicator: Flashing reticle upon startup if batteries are at 20% of battery life.Auto Shutdown: At 8 hours – programmable to 4 hours-Model 510 AA -Order code 512.A65-Waterproof & Submersible To 10 ft depth -Battery AA lithium, alkaline, or rechargeable-Battery Life (setting 12) 500 hours continuous-Length of sight 5 inches (131 mm)-Reticle Options 65 MOA ring w/ 1 MOA dot-Weight: 11.5oz (326 grams) USA Shipping is FREEInternational shipping varies. Payment: Payment is due within 2 days of winning. We accept payments via PayPal, Visa, MasterCard, Discover and American Express. Local pick-up purchases will also be paid for with cash. Shipping:International buyers should message us for shipping quotes prior to purchase.USA Shipping is regularly free. We ship through USPS First Class or Priority Mail. We ship items within 2 business days of receiving payment except for Dropshipped items. We combine shipping on more than one purchases. Cost of combined shipping varies. Larger items or large lots will also be picked up locally. Returns:We accept returns on all new and used items unless the item is a consignment item or being sold as-is. Buyer should contact us within 7 days of receipt of item(s) if there is a problem and want to return the item(s). We can not accept returns on certain brand new in the retail packaging products that were opened and used by the buyer. If the returned item(s) are received broken, consumed or damaged because of customer use, We can not issue a return. The buyer is responsible for return postage and packaging.