The Koress K3 hookahs is a superior Russian made hookah. The innovation that went behind this unique design is groundbreaking. The adjustable diffuser of the Koress K3 comes with a Pulley system that allows the hookah to be more restricted if need be and wide open to make the draw smooth. the invisible purge shoots out from the slight openings along the stem. Moving the inner pulley system up or down allows you to adjust the diffuser, and boom you're a pro shisha smoker now.