I'm tinkering with the KP Spitfire Vc (tropical) and as I was assembling the Volkes filter, it dawned on me that all the various kits I've seen or assembled that had a Volkes filter, represented the 'chin' as a vast, empty cavern with a hole in front.  Surely there's a screen or grill inside that empty hole that normally can be seen, isn't there?  Anyone know?   Scott