Period defined in an Act of Accession during which temporary measures apply between the date of accession and the date of the full application of the founding Treaties and secondary legislation in the acceding Member State (different areas of Community law may be subject to different transitional periods of different lengths) (1) Most of the New Approach directives contain a final clause introducing a transitional period. A distinction must be drawn between this transitional period and any transitional period provided for the harmonized standards and setting the date until when the previous standard, which has been revised, can still apply. The transitional period is the time which elapses between the date on which a directive enters into force and a subsequent date, set in each directive, until when the national measures implementing the Community directive exist alongside the previous national regulations. Throughout this period, manufacturers (or their authorized representative established in the Community) have a choice between placing on the market and/or putting into service in any Member State either a product conforming to the directive or a product conforming to the national rules (2)