Abstract: A tube closure of elastomeric material having specific properties has an open end, a closed end and a side wall defining a tapering outer frustoconical surface. The side wall has a predetermined thickness at its thinnest point, which is determined in connection with the angle of taper of the outer frustoconical surface and the properties of the elastomeric material to provide a seal with high integrity over a range of tube sizes. The closure has a radially extending flange of predetermined thickness by which the closure can be removed from a tube by a pushing force. The closure has an inner surface for sealing against an outer surface of other tubes.

Abstract: A cap for sealing evacuated tubes has a plurality of sealing surfaces to seal tubes of various sizes and a septum of self-closing material to permit a needle to pass for the withdrawal or injection of fluids. The sealing surfaces are defined by a plurality of annular bands extending in series from a top wall, as well as a skirt which depends from the top wall and surrounds the annular bands.