You can ship nunchucks to Massachusetts state only if you are a licensed martial arts school or a student of a licensed martial arts school. By choosing shipping to Massachusetts and checking out, you declare that fact and, as well, declare that by law you are allowed to buy and posess product that you are buying.
It's your responsibility, as the buyer, to be aware of your local laws regarding the purchase and use of martial arts accessories. By checking out, you agree to these terms and conditions and take on the responsibility for the purchase and usage of these items in compliance with your local laws and regulations.