This factory-matched number kit includes 4 sets of the letters A-Z and the numbers 0-9, for a total of 146 decals. These number kits resist fuel, fading and scratches. They are UV Coated for protection from the sun and meet the US Coast Guard guidelines. Registering your boat means applying for and getting a certificate of number and the number itself. The registration number is actually a combination of letters and numbers normally beginning with the abbreviation of the State in which the boat is registered. The certificate of number is small and must be on the vessel whenever it is being used. A validation decal is required to be placed along side the numbers on the port side of the vessel. Some states require decals on both port and starboard side. This decal may need to be renewed annually. Your state's law may say the bow number must be permanently attached to each side of the forward half of the boat. But each state's laws are different, so check to be sure.