Carnets are “Merchandise Passports.” They are international customs documents that simplify customs procedures for the temporary importation of various types of goods. In the U.S., two types are issued: ATA and TECRO/AIT Carnets.
ATA Carnets ease the temporary importation of commercial samples (CS), professional equipment (PE), and goods for exhibitions and fairs (EF). They facilitate international business by avoiding extensive customs procedures, eliminating payment of duties and value-added taxes (minimum 20% in Europe, 27% in China), and replacing the purchase of temporary import bonds.
TECRO/AIT Carnets, used between the U.S. and Taiwan only, appear similar to, and serve the same function as the ATA Carnet. TECRO/AIT Carnets result from a bilateral agreement between the US and Taiwan, covering only commercial samples (CS), and professional equipment (PE). Merchandise entering countries in addition to Taiwan may also be accompanied by an ATA Carnet.
US Council for International Business - Carnets