This is a typical carnival D-510 except that it has a bronze threaded insert molded into the glass, instead of the typical mandrel-formed threads in glass. At first I didn't believe it, I thought it was just a lead or zinc bushing sleeve used as an expansion buffer on metal pins. But after close examination, you can see the molten glass is formed around the insert, especially in the dome where there are trapped air pockets where the top of the insert was not completely covered with the molten glass. Also, the bronze is discolored on both sides from being inserted into the hot glass. Hit the "next" button for a few more pics. EIN 110