The PARA-TECH DELTA Drogue uses the "guide surface principle". The design is a triangular "Delta" shape that provides strong uniform flow separation at all leading edges. Shape retention is achieved by the pressure of the water inside (similar to the "Ballute" drogues used in aerospace applications). The relatively small mouth at the leading edge makes it extremely unlikely that one will get turned inside out (a problem associated with large cones and small parachute drogues). Also, the three ears of the DELTA Drogue have the effect of increasing the Drogue's drag as speed increases. The PARA-TECH DELTA Drogue is extremely SIMPLE in design and construction. So simple that it is made from heavy duty vinyl coated material