which is a full cross sectional front view of the mold 1 of fig1 through line 100 100 wherein like numerals indicate like components there is shown in addition the molded product 15 the centered opening 16 in the stem 13 a connection 17 for injected gas a gas valve 18 injection gate 19 for liquid molding material opening 20 in the top surface 8 of the core 7 all of which will be discussed infra further there is shown confronting flat surfaces 21 and 21 u2032 for the upper mold segment 3 and the lower mold segment 5 respectively concavity 22 for the upper mold segment 3 and the concavity 22 u2032 for the lower mold segment 5 each of the concavities have an opening 23 for the upper mold segment 3 and 23 u2032 for the lower mold segment 5 and the respective openings 23 and 23 u2032 run through the upper mold segment 3 and the lower mold segment 23 u2032 respectively the opening 23 u2032 exits through the bottom surface 6 of the lower mold segment 5 the opening 23 in the upper mold segment 3 runs through the upper mold segment 3 and exits through the upper surface 4 of the upper mold segment 3 it should be understood that eventhough the figures herein illustrate the concavities as being hemispherical concavities it is contemplated within the scope of this invention that such concavities can have various configurations especially where the product.