http://www.billingsoptical.com/red-dot-sight/compact-red-dot-sight/ Billings Compact Tactical Red Dot Sight are for all of your hunting, tactical and outdoor needs. enjoy a high reputation because they are extremely durable, withstand high recoil forces and have long battery life. 1. Introductions Billings compact tactical red dot sight enjoy a high reputation because of the extremely durable construction to withstand high recoil forces and extremely long battery life-more than 100,000 hours. With parallax-free design, you can shoot with both eyes open to acquire your target. 2 types of intensity adjustment of dot brightness can be available. One type is with 12 positions of red dot from 0-11, and another type is with 6 positions of red and green dot. You can make the choice by yourself. The high grade aluminium alloy with anti-scratch finish is the base of waterproof, shockproof and fog proof. 2. Specifications ModelPowerObjective Lens Diameter(mm)Tube diameter(mm)F.O.V@100ydsEye reliefLength (inch) ABS RD301X263050'Unlimited4.33 RD1X251X2125.440'Unlimited4.33 RD1X301X263052'Unlimited4.33 RD1X30IM1X3038.268'Unlimited3.82 RD1X30IM/221X3038.268'Unlimited3.82 RD1X42IM1X424580'Unlimited3.76 RD1X50IM1X505288'Unlimited3.76 RD2X30IM2X3038.226'Unlimited5.2 RD1X30 3 dot Xbow1X263052'Unlimited4.33 RD1X30IM 3 dot Xbow1X3038.268'Unlimited3.82 RD1X341X34/74'Unlimited3.23 DG1X30IM1X303970'Unlimited3.8 3. Product Features 1) Compact and light weight with rugged construction 2) Nitrogen Purged aircraft-grade aluminum alloy scope body 3) Fog proof shockproof and waterproof 4) Unlimited eye relief and Free parallax 5) Bright and clear dot 6) Fully-coated and 27-layered inner lens coating lenses 4. FAQ 1) --Are you trading company or manufacturer --- We are professional manufacturer of scopes and red dot sights and accessories with more than 20 years' experience. 2) --Can you support OEM and ODM? --- Yes, of course, we have cooperated with our OEM and ODM customers from 2000 to support them to become the worldwide famous brands.discount Compact Red Dot Sight website:http://www.billingsoptical.com/red-dot-sight/compact-red-dot-sight/