Carnet

A document that lets goods enter a country temporarily without duty and import taxes being paid, on the basis that they will leave again unchanged. Commonly used for exhibition goods, professional equipment, samples and commercial vehicles.

It works because a guaranteeing body stands behind the duty. If the goods are not re-exported within the period allowed, the guarantee is called and the duty becomes payable - so a carnet is a deferral secured by someone else, not an exemption.