"TRACER PATTERN" contains a tracer ball that travels with your shot pattern to show where you are hitting. This tracer ball is ballistically matched and remains near the center of the shot pattern for the effective range of a regular shell. "TRACER PATTERN" allows your hand-eye coordination to develop more quickly, allowing you to adjust your aim, reduce training time and wasted shots-thus improving your accuracy! The composition of the tracer compound is non-phosphourus & are non-corrosive to your shotgun & is fully visible day or night. (CANNOT BE SHIPPED TO NEW YORK CITY OR SURROUNDING AREAS.) 2 3/4 round