Merely adopting and using a trademark gives you certain rights. Registering your trademark protects those rights. The Federal Registration mark, indicated by a capital 'R' with a circle around it, is an official announcement that this product, marketed under your name or logo, is officially yours. Anybody can begin to market a product under any name. If you had a similar existing product under that name, you have the right to stop anyone else from using the name, but first you'd have to prove that you had your product on the market first. A registered trademark is the most absolute proof you can offer, and it can also help you avoid the huge legal bills that can occur when somebody tries to protect an unregistered name. If you plan to market your product outside the U-S, a registered trademark in this country is invaluable in registering your product in other countries. You can also file your trademark with the U-S Customs service to prevent infringement from imported goods.