Choate Tool Mossberg 500/600/590 Shell Follower12 Gauge. It will protect your spring and you will be able to tell from a glance if your gun is loaded or not with the Hunter Orange Color of the follower. Specifications for Choate Tool Mossberg 500/600/590 Shell Follower: Manufacturer: Choate Tool Country of Origin: USA Features of: Safety orange Polymer construction Package Contents: Choate Tool Mossberg 500/600/590 Shell Follower Choate Tool CMT-02-05-02: Mossberg 500/600/590 Shell Follower12 Gauge