The preform mould has two halves, a stationary lower one and a movable upper. The cavity dimensions are determined by the core rod layout. The outside physical dimensions are governed by the specific machine upon which it is to be mounted.

Temperature control is critical and is an essential in the layout of the cavity design. Temperature control zone channels are created by drilled holes in the mould body to form the circulation of the liquid cooling system. These channels are connected to separate individually controlled zones. The number and location of the zones are a critical factor since it affects the efficiency of the final production. The positioning of the zones along the cavity profile is such that the temperatures are varied to cause a uniform blowing the parison.