Preform (1) or preform assembly for blow molding a container (23), wherein the preform of preform assembly has a neck portion (4), a lid element (16) being provided at the neck portion, an opening extending into the neck portion, providing access to an internal space of the preform or preform assembly. Method for blow molding a container. Container blown from a preform or preform assembly.

A dual container, including a container body and a mouth portion attachment. The container body includes an inner bag and an outer shell that is disposed to cover the inner bag, and the inner bag is configured to be extractable from the container body, and the mouth portion attachment is attached to a mouth portion of the inner bag and is configured to be removable from the mouth portion.