A cap for a container, the cap comprising: a skirt component formed of a metal material, the skirt component comprising an annular outer sidewall defining a skirt cavity that extends along a skirt axis and has an open bottom end, the skirt component comprising a first interference element; and a seal component formed of a plastic material, the seal component comprising an annular seal sidewall having a threaded inner surface configured to mate with a threaded outer surface of a neck of a container body, the annular seal sidewall defining a neck cavity having a closed top end and an open bottom end for receiving the neck of the container, the seal component comprising a second interference element that mates with the first interference element of the skirt component; wherein the seal component is mounted to the skirt component and located within the skirt cavity so that the annular outer sidewall of the skirt component circumscribes the annular seal sidewall of the seal component; characterized in that the skirt component comprises: an inner annular sidewall that is surrounded by the outer annular sidewall so that an annular space exists between the inner and outer annular sidewalls of the skirt component; and an annular skirt end wall, the inner and outer annular sidewalls (109, 103) of the skirt component extending downward from the skirt end wall; wherein the first interference element of the skirt component is located on an inner surface of the inner annular sidewall of the skirt component; and wherein the second interference element of the seal component is located on an outer surface of the annular seal sidewall. a skirt component formed of a metal material, the skirt component comprising an annular outer sidewall defining a skirt cavity that extends along a skirt axis and has an open bottom end, the skirt component comprising a first interference element; and a seal component formed of a plastic material, the seal component comprising an annular seal sidewall having a threaded inner surface configured to mate with a threaded outer surface of a neck of a container body, the annular seal sidewall defining a neck cavity having a closed top end and an open bottom end for receiving the neck of the container, the seal component comprising a second interference element that mates with the first interference element of the skirt component; wherein the seal component is mounted to the skirt component and located within the skirt cavity so that the annular outer sidewall of the skirt component circumscribes the annular seal sidewall of the seal component; characterized in that the skirt component comprises: an inner annular sidewall that is surrounded by the outer annular sidewall so that an annular space exists between the inner and outer annular sidewalls of the skirt component; and an annular skirt end wall, the inner and outer annular sidewalls (109, 103) of the skirt component extending downward from the skirt end wall; an inner annular sidewall that is surrounded by the outer annular sidewall so that an annular space exists between the inner and outer annular sidewalls of the skirt component; and an annular skirt end wall, the inner and outer annular sidewalls (109, 103) of the skirt component extending downward from the skirt end wall; wherein the first interference element of the skirt component is located on an inner surface of the inner annular sidewall of the skirt component; and wherein the second interference element of the seal component is located on an outer surface of the annular seal sidewall.