The Holosun HM3X Magnifier features an integrated flip-up mount with fixed 3x magnification, engineered to make transitioning from close quarters to intermediate-ranged targets fast and easy by quickly flipping up when engaging with targets at extended ranges and flipping down and out of the way when you need true 1x magnification for close quarter targets. The Holosun HM3X features a CNC-machined aluminum QD 1913 Picatinny rail mount design for quick installation and removal on my rifles and carbines while O-ring seals keep moisture out for IP67 waterproof performance. The HM3X also boasts 2.75” of eye relief and features ultra-clear glass lenses for optimal clarity. If that's not enough, this magnifier is backed by a lifetime warranty for years of faithful service you can depend on.