BoXXer’s new DebonAir+ twin tube design is unlike any air spring we’ve made before—and it rides that way. We boosted the air spring shaft diameter from 10mm to a hollow 14mm shaft, creating extra negative volume for the air spring. Adding the twin tube sleeve lets us precisely control the different spring volumes: positive, negative, and casting (that air trapped in the lower leg). This optimizes positive air chamber volume for that hole-swallowing linear spring curve. You can use every single millimeter of travel (if you need it). Additionally, at the bottom of the stroke, a new Jounce bottom-out bumper gives you soft, clank-free landings off the biggest drops.