This specific customs procedure concerns goods imported into a customs area for a limited period of time and then re-exported in the same condition.
In fact, you must guarantee the duties and taxes linked to these products with the customs authorities of the countries concerned.
Be sure to retain a clear copy of the Carnet for your records.
Generally, local customs will request that the goods and Carnet be brought to the local office prior to Carnet expiration so that the Carnet may be properly discharged and duties, taxes, and penalty paid.