Abstract: A blow molded container for liquids is vertically stackable with geometrically similar containers. Each container has a unitary body formed of an extruded parison the thermoplastic material. The containers have a bottom surface which includes a release groove bifurcating the bottom surface, the release groove including a remnant portion of the parison forming a web-like external rib depending downward within the release groove. A top surface of the container includes an opening closed by the cap and includes a notch which receives the remnant portion of the parison of a geometrically similar container stacked thereon to laterally locate and stabilize the relative positions of the stacked containers.