Liquid Force was really creative in the design of this binding but not as much in the naming of it. When the binding gives the rider the ultimate in high performance flexibility, why not call it the FLEX? During the testing phases of this model, Shane Bonifay and the rest of the team riders that wanted a softer flex in a high end boot were blown away by how maneuverable, yet secure this binding made them feel on the board. Combining a welded vented upper construction with a 3-in-1 closure system makes this binding one of our lightest, as well as one of our most adjustable. The point of the 4D Chassis System is to make the ride more responsive due to the fact that the board and binding can flex together… the FLEX 4D binding provides that type of feel and performance perhaps more than any of our others!