The expanded pumping chamber holds 4 1/2 cubic inches of air

Similar to the volume of air contained around the foot

EXHAUST

The pumping chamber compresses,

and the contents is propelled out

through the exhaust.

With the exhaust complete

the pumping chamber is fully compressedc

INTAKE

The chamber comresses, and fills with heated moist air drawn from around the toes. Fresh air then enters around the top of the shoe.