This manual provides practical guidance to National Ozone Units, implementing agencies and customs trainers on how to organize and conduct Train the Trainer and subsequent training to customs officers. It includes generic agendas, concept notes, evaluation questionnaires as well as all relevant training materials and overheads. It focuses on the identification of ODS and ODS-containing mixtures, products containing and equipment based on ODS as well as the different smuggling schemes. It should be used in conjunction with the complementary.