B4H70-67026 is the product code for the HP Latex 360 Carriage Belt. It is a 64-inch belt that is used to move the printhead across the platen. The carriage belt is a critical component of the printer and must be replaced periodically to ensure optimal performance. The replacement interval will vary depending on the amount of use the printer gets. However, it is generally recommended that the carriage belt be replaced every 12-18 months.