Dual-function spring

An injection device for dispensing a product, the injection device comprising

• a. a housing;
• b. a product container holder connectable to the housing, said holder being configured for accommodating a product container, wherein said product container holder is sleeve-shaped and comprises an opening through which the product container can be inserted into the interior of the product container holder,
• wherein at a side the product container holder comprises a region through which it can be seen from an outside into an interior of the product container holder;
• c. a plunger rod accommodated for displacement relative to the product container;
• and
• d. a spring element configured to act on said product container accommodated in said product container holder to push the product container into a fixed seating within the product container holder.