J.C.Wren wrote:
Side relief holes actually increase the volume of
air, via a venturi
effect. You do get reduced air speed, but more volume. They're also a
safety feature of some kind, but damned if I've figure out how.
--John
It's so you can't blow air through your skin into your blood stream, by
holding the end against some body part.
Chad Fernandez
Michigan, USA