Monstrum Tactical R40 40mm Red/Green Dot Sight 1x40mm reflex sight in a heavy duty, weatherproof scope enclosure True dot reticle with illumination in red and green with five brightness settings, for a clean sight picture regardless of lighting conditions or environment Parallax free with flexible eye relief Mounts easily to any Weaver/Picatinny rail equipped flat top rifle Sturdy anodized aluminum construction with black matte finish