A closure for a container neck having a crown, a reduced diameter portion, a downward facing shoulder, and an enlarged diameter portion. The crown defines an opening and an outwardly extending locking bead. The closure includes a cap, a skirt, a well, a frangible membrane, a pull ring, and a retainer. The skirt depends from the top and is adapted to fit around the crown and the enlarged diameter portion of the container neck. The well includes an upper side wall depending from the top, an inwardly directed shoulder located adjacent a bottom of the upper wall, and a lower side wall depending from the inwardly directed shoulder. The lower side wall has an interior surface and the lower side wall terminating at an open bottom. The frangible membrane in the well closes off the well and includes a line of weakness frangibly connecting the frangible membrane to the lower side wall adjacent the inwardly directed shoulder. The pull ring is attached to an upper surface of the frangible membrane. The pull ring is positioned within a recess and substantially below the top. The retainer structure is adapted to engage the downward facing shoulder of the container neck. The retainer structure includes a plurality of inwardly and upwardly extending retainer flap that engage the downward facing shoulder of the neck. The retainer structure further includes a hinge connecting each flap to an internal surface of the skirt.