The RNZAF in the South-West Pacific theatre later in WW2 used a lot of standard US Navy (and sometimes USAAF) flying gear, including throat mikes. I have seen the official instructions for using these items, and the equipment itself was designated with an ANB number (ANB = Army - Navy - British), an extension of the AN joint-service system for standardised equipment. The throat mikes were used mostly by fighter pilots, but also later by PV-1 crews, in association with the large, spring-steel headband-type earphones. For aircrew who did not have to continually breathe oxygen, this combination was a lot more comfortable than the traditional oxygen mask and helmet wired with earphones. I have seen photos of RNZAF Corsair pilots late in the war wearing an American fatigue cap (made from HBT), with large earphones and throat mike, apparently ideal for fighter-bomber duties below 15,000 feet. As has already been pointed out, throat mikes also rapidly became standard for armoured fighting vehicles, certainly with the Americans and Russians, and this was in WW2 as well. This was presumably because of the very limited room inside such vehicles, and tucked under your chin the throat mikes were well out of the way should you have to move vigorously around the interior without accidentally snagging any of the interior equipment. There are also some excellent colour photos of trainee USAAF pilots in P-40s wearing similar rigs in 1944 to be found in books such as Jeff Ethell's volumes, complete with caps, and sprung-headband earphones, and slid back canopies - probably in the mainland southwest, and real warm!