I have never seen these before and they are pretty much solid glass except for a small cavity at the bottom and no wires can pass through them. However, they apparently screw into something and have a rubber O ring gasket that seals the base(I removed the gasket but still have it) and by the rust in the ribs, they appear to have held wires. Does anyone know what there "bushings" really are or go to? This is 4 1/2" tall X 2 6/8" wide at the top.

Thanks Chris