I'm not sure if it's true, but I've seen a documentary a while ago about Russian ice divers and one of the divers said they preferred the old piston regulators (looked like old pre plastic era mk2's) for ice diving because supposedly they don't build these huge chunks of ice and the water contact actually transfer heat back easier so that they thaw more easily.
It seemed very counterintuitive to me, since we're always told pistons are not reliable in cold water.
It seemed very counterintuitive to me, since we're always told pistons are not reliable in cold water.