Closures are provided consisting of a lid or cap member and a container member. These are inter-engageable with one another. The lid or cap member has a skirt and the container member has an upstanding rim, each of which is of generally polygonal shape. Located on each of the facing walls on each side of the polygonal shape are inter-engageable projections. The inter-engaging surfaces of the projections run substantially in a plane perpendicular to the axis of the polygonal shape and are of relatively small angular extent about that axis. The material of one or both of the skirt and container portion is resiliently elastic. The closure may be assembled with an axial push, and removed by twisting.
