rubber inserts destroyed the molds at the behest of Groco who had just introduced the bronze cones in their new line-up. The bronze cone type were alright but most I have seen would leak or "weep" and could not be made as "dry" as the older rubber inserts. Of course now they have the ball valves and will probably discontinue the bronze cones at some point (if they haven't already). Groco parts have always been wildly overpriced in my view.