Jamie - are these the ones that you have to cover with some sort of heatshrink because the outside is conductive? You guys are seriously tempting me to give the ole crack a little update!
Hi skeptic I did originally cover mine with a precautionary covering of clear heat shrink prior to fitting. However after taking one apart they look to be very well insulated both in the ends and body from the metal shell with a generous wrapping of teflon after the actual foil part ends. I suspect the heat shrink is actually not required. Interestingly the internal leads that connect to the steel pins for hooking up look to be made of silver wire!
I have made some woody versions but have yet to try them