N-Number Format

N-Numbers consist of a series of alphanumeric characters. U.S. registration numbers may not exceed five characters in addition to the standard U.S. registration prefix letter N. These characters may be:

• One to five numbers. Example: N12345.
• One to four numbers followed by one letter. Example: N1234A.
• One to three numbers followed by two letters. Example: N123AB.

Additionally, the letters I and O are not to be used to prevent the confusion with 1 and 0. Also, no N-Number may begin with zero.