Brilliant flourescent red on a white background presents a highly visible aiming point for precise sight alignment. Offers excellent contrast to easily align sights or crosshairs. Features a grid divided into 1" squares to help you quickly determine sight adjustments. ST-3 has an easy-to-see red bull that really stands out in all light conditions; perfect for target shooting or sight-in with iron sights or scopes. ST-4 has diamond center with bold 90° alignment lines. Five separate sighting points lets you shoot several groups before replacing target.