Participating apprentices should be older than 16 years, they normally spend four days each week in an enterprise to acquire work experience, and one day in an MITD training centre for theoretical and technological back-up. Apprentices undergo block release (two weeks’ duration), centre-based training at the start of the apprenticeship to enable them to develop the basic initial skills required for engaging effectively in the on-the-job training. Hie conditions of apprenticeship training are governed by a contract which is signed by the employer and the apprentice (or their responsible party).