The present invention relates to an assembly (101) comprising: an injection device (1) comprising a container (2) for a product, said container comprising a distal tip (3), an adaptor (5) comprising a ring (6) mounted onto said distal tip (3), characterized in that said assembly (101) further comprises a heat-shrinkable film (9) covering part (2a) of said container (2) and part (5a) of said adaptor (5), said film (9) maintaining said adaptor (5) blocked in rotation and in translation with respect to said container (2) when said film (9) is in its heat-shrunk condition. The invention further relates to a method for manufacturing such an assembly.
