This mid-capacity G&P M16 airsoft rifle magazine illuminates airsoft tracer BBs and is designed to be used with Tokyo Marui M16 airsoft rifles. The blue LED inside the magazine feeding tube illuminates each tracer BB in the magazine before it's fired from your gun! The button on top of the magazine is activated automatically once you begin loading the magazine. Powered by 2 AAA or 3 N batteries. Simply unscrew the small screw on the bottom of the magazine to access the battery compartment.