The Mossberg 500 has proven to be one of the most versatile and reliable shotgun platforms available, offering a model to fit every application, and every user from our households, to law agencies, to military worldwide. The FLEX is a modular system of shotguns based on the legendary model 500 with the LTS (Tool-Less Locking System). This system consists of three convenient connecting technologies, that come together to bring another level of flexibility to your hunting and sport shooting endeavors. One locking pen is for the stock, one for the forend, and one for the recoil pad. The All Purpose series is set up for any of your shotgun needs but easily allows you to change the stock, forend, or recoil pad for a specific need.