I'm going to build a bottomfeeder, but one thing's missing from my materials. It's the flexible feeder tube that connects the bottle to the battery connector. I formerly owned a RSM, and I have the metal tube that is soldered into the positive post and goes through the dropper bottle nipple. I'm unaware of the material that the flexible tubing is made of or a vendor for this material. Could someone point me in the right direction please? TIA!