Increase the range of your standard red-dot optics with this Vortex VMX-3T Magnifier that sports a simple, fast and effective push-button design. Multicoated lenses deliver optimum light transmission. Internally nitrogen purged for waterproof and fogproof performance. Hard-coat anodized for long-lasting durability. Allows for lower 1/3 cantilever mount or absolute co-witness mount.