ITF-14 is the GS1 implementation of an Interleaved 2 of 5 (ITF) bar code to encode a Global Trade Item Number. ITF-14 symbols are generally used on packaging levels of a product, such as a case box of 24 cans of soup. The ITF-14 will always encode 14 digits.
The thick black border around the symbol is called the Bearer Bar. The purpose of a Bearer Bar is to equalise the pressure exerted by the printing plate over the entire surface of the symbol, and to enhance reading reliability by helping to reduce the probability of misreads or short scans that may occur when the scanner is held to a bar code at too large an angle. Such instances of skewed scanning cause the scanning beam to enter or exit the bar code symbol through the Bearer Bar at its top or bottom edge, forcing the scanner to detect an invalid scan since Bearer Bars are much wider than a legitimate black bar.