... "emergency locking retractor" means a retractor which, in normal driving conditions, does not restrict the freedom of movement of the wearer of the safety belt. It has a length adjusting device which automatically adjusts the strap to the wearer, and a locking mechanism actuated in an emergency by: 1.8.4.1. deceleration of the vehicle, extraction of the strap relative to the retractor or any other automatic means (single sensitivity ), or 1.8.4.2. any combination of these factors (multiple sensitivity).