Inside the PAC, a Vortex Tube spins the supplied compressed air, separating it into hot and cold airstreams. The cold airstream is delivered to the vest via a ducting tube, while the hot air exits out the side of the PAC unit.
The low-pressure cold air flows into the Diffuse-Air Vest's perforated inner lining, which distributes the refrigerated air over the upper body.
Unfolding the collars of the vest will reveal air holes to cool the neck and face.
Model 220 uses hot and cold air from both ends of the vortex tube to create a fully adjustable heating and cooling option.
