The Nas Modular System was made for when a diver wanted to dive using a twinset or multiple cylinders. Although the system is designed with technical divers in mind, it can also be used by recreational scuba divers, The wing can be streamlined by tightening the elasticated straps (internally) which will reduce the wing to approx 45lb but will still expand to 85lb when fully inflated, When the wing is streamlined a single cylinder can be used ideally with one of the nas weighting system and the diver can up grade the system to a twin set as needs and experience demands