1) Most important: liabilty insurance. This protects you if anyone is injured by your products (or by you in the course of work--e.g. if while demo'ing a club for someone, you accidently hit them in the head).2) Since you are manufacturing what I assume (as a non-golfer) are expensive items, and presumably using potentially valuable equipment to do so, you want to get insurance covering your inventory and equipment.3) If this will be a major part of your income (instead of a sideline), you probably want "business interruption" insurance to protect you in case something beyond your control disrupts your operations--this insurance will pay some amount or portion of the profits you'd have otherwise made.