The Strike Industries FAT COMP (FC)! The FC comes in four different versions and is designed to integrate seamlessly with the SI Cobra Dummy Suppressor. The FAT COMP features four different styles made to fit any desired look. Its 1.5” diameter can also fit inside most free float handguard rail systems and directly attaches to any AR barrel with a 1/2”x28 thread pitch. All FAT COMPs are made of steel and coated with a matte black finish.