Golf component sales. Some of these sites also sell custom assembled clubs, but the bulk of their business is selling heads, shafts, grips, tools, and supplies for other club builders.
If most of your business is selling assembled clubs from components, and only a small part is selling components to club builders, list your site in the Custom category. All sites submitted in Shopping/Sports/Golf should provide means for the general public to purchase product online, i.e. a "shopping basket", order form, or telephone order line.
For general information on what belongs in Shopping, see the Shopping FAQ and the Shopping Description.