The included nonrotating circular polarizer features a 1.6-stop compensation. The ND4 requires a 2-stop compensation the ND8 requires a 3-stop compensation the ND16 requires a 4-stop compensation the ND32 requires a 5-stop compensation and the ND64 requires 6 stops of compensation. This allows you a choice in adjusting your iris settings. An included magnetic case holds three filters so you can carry them in a pocket and have the filters ready at a moment's notice.