A bar code symbology that is discrete, variable length, and self-checking. It requires loose printing tolerances. It can be used interchangeably with Code 39 when higher density printing is required. The character set is the same as Code 39: A – Z uppercase, 0 – 9, dollar sign ($), period (.), slash (/), percent (%), space ( ), plus, (+), and minus (-). It can be extended to full 128 character ASCII by use of a four-character encoding scheme (see full ASCII). Its maximum density is 14.8 characters per inch.