You probably know exactly what these are, but I have no Idea. The brass studs on these two are different lengths, 0ne is 6" and the other is 5 13/16" otherwise they are Identical, double brass nutted on either end with rubber gaskets behind, and two rubber insulating gaskets between the two bells. The Bells are clear, 1 9/16" in length and have "Pyrex made in U.S.A. Pat. 1 700 066" embossed on the bottom flange of the bells. I believe this is the patent for the glass composition. How's $30 shipped for the pair sound? Even if you aren't interested, would someone be so kind as to drop me a note and set me straight as to what these things are? No feePayPal only, ships to the lower 48 only. If you want them shipped to Canada, It'll be a little more. Thank you for looking.