The present invention relates to a content-reservoir/product applicator assembly that comprises a refill associated to a housing that supports an applicator for applying a product, the assembly being associable, in a detachable and interchangeable manner to a storage package, the storage package storing the assembly. The refill contains cosmetic products and comprises a case; a neck; a housing; and an applicator. The applicator is a substantially spherical, continuous rotary surface and is associated to the housing. The housing is associable to the housing by thermal welding. The refill is made from a squeezable flexible material.