Abstract: A closure assembly for use on a container neck finish has an inner cap which threadedly engages the neck finish and an outer cap which is received by the inner cap. Torque lugs on the outer cap cooperate with abutment formations on the inner cap such that rotation of the outer cap drives the inner cap onto the neck finish. Cooperative engagement between the two caps is achieved by downward axial movement of the outer cap. An arrangement of ramp sections on the inner cap and an arrangement of interior lugs on the outer cap provide an assist feature helping to pull the outer cap in the axially downward direction. Another feature of the closure assembly includes a spring-biasing relationship between the inner and outer caps. The inner cap also includes an abutment structure which cooperates with the container to limit drop test deformation of the container.