In the firearms industry, side battery compartments are essential components found in many AR-15 uppers. These compartments are cleverly designed to house batteries for red dot sights, holographic optics, and other electronic accessories. Their location on the side of the upper receiver allows easy access and quick battery replacement. Ensuring your optics are always ready when you need them. Side compartments enhance the overall functionality of your AR-15, promoting quick target acquisition and improved shooting accuracy. Don’t compromise on performance; invest in an AR-15 upper with a battery compartment to keep your optics powered and your shots on target.