The mold and die produced to manufacture this part were made from an  Original  N.O.S. GM part.  They turned out beautiful.  This part supports the heater core tube that passes through the fiberglass  A/C evaporator box.  Without this seal in good condition the weight of the heater core supply hose can break the solder joint at the heater core.  At this price, it is not worth the risk of over heating your engine or damaging your interior from anti freeze or just the pain and cost of replacing your heater core.  The pictures show the seals great  fit on the car and also a cut away cross section to show the exact metal insert.  100% MADE IN THE USA !!!  Thank you!