The Vortex VMX-3T Magnifier features O-ring seals that prevent moisture, dust, and debris from getting inside the tube for reliable performance in all environments. The Vortex CMX3T Gun Mounted Scope has barrels that are fillled with nitrogen gas to inhibit internal fogging. Simple, fast, effective-the push-button design of the VMX-3T engages and disengages the flip-mount, allowing the magnifier to lock in place. The result, 3x magnified or unmagnified views at will. Optics are fully multi-coated for optimal light transmission. Lightweight and tough; hard-coat-anodized machined-aluminum construction ensures durability. Internally nitrogen purged for reliable waterproof/fogproof performance. Ultimate magnified versatility for virtually any AR-height red dot sight. The Vortex VMX 3T Waterproof Magnifier comes with a flip mount and has a matte black, hard-coated anodized finish for durability.