The SPARK S4 is the enclosed red dot sight of fierce optics , with Multi-Reticle system, options of three different reticles. With the Motion Activated system, while it is turned on, the red dot illumination will go to sleep after five minutes of inactivity. When any motion or vibration is detected, it instantly switches on the illumination at the previously used brightness setting. The max recoil is up to .45 acp ammunition, provides a wide field of view, and lets you get on target quickly.