TAC Optics Red Dot Sights can be easily used with both eyes open, increasing the shooter's awareness of the surrounding environment and providing faster target acquisition due to the parallax free design, as the dot follows the movement of the user's eye while remaining fixed on the target. Engineered for greater speed and accuracy, these sights allow you to focus on the target rather than a reticle, thus increasing accuracy. The Mini Cannon Red Dot is a dynamic red dot in a compact 3-inch package. It features a choice of user-selectable red dot reticles (dot, circle dot, crosshair dot, circle crosshair dot), with 11 brightness level settings. It is also very rugged, with waterproof, shockproof and fogproof construction.