Abstract: A cavity member is disclosed for use in an injection molding machine. The cavity member has one portion which includes a molding surface for forming the molded article and a second portion for reducing heat transmission to the first portion. The second portion forms a cap on the nozzle end of the cavity member and includes an aperture aligned with the gate of the cavity member so as to permit plastic from the nozzle of an injection molding machine to enter into the mold. The cap includes channels which can cooperate with pockets in the nozzle end of the second portion for liquid cooling. The nozzle is spaced from the cap by a short distance to provide a thermal break which break can be filled with plastic from the injection molding unit to provide further insulation.