Simple and sturdy, the adaptive receiver mounted shell carrier for Mossberg keeps six 12 gauge shells at the ready. No need to fumble for shells, just quickly and conveniently Reload right from the side of the receiver. Whether for home defense, sport shooting or law enforcement use, the durable shell carrier is up to the task and ready to perform in the harshest of conditions. Important for end Advisory: if your shotgun is equipped with a field grade for end that extends onto the sides of the receiver, it will hit the shell carrier and not cycle fully. To remedy. shorten the length of the for end or equip with an alternate, compatible for end such as adaptive' s ex-performance or adaptor..