Jacket comfortable on surface but tilts. Wing enables horizontal trim. Backplate+harness is DIR technical diving foundation.
The choice between a traditional jacket BCD and a wing with backplate is one of the most recurring debates, with discussions about specific models such as the XDeep Hydros, Zeos, and Zen, the Mares XR-REC, or the Subaqua Aqua BCD. Divers ask where to rent a wing before buying, how to attach weight to a backplate, and what the real difference is in buoyancy and comfort in the water.
The jacket distributes buoyant air around the torso, being more comfortable at the surface but tending to tip the diver into a vertical position. The wing concentrates all volume at the back, facilitating a hydrodynamic horizontal position. Modular systems (backplate + harness + interchangeable wing) are the foundation of technical diving and the DIR philosophy: they allow the wing to be adapted to the type of cylinder, worn components to be replaced, and the fit to be personalized with millimetric precision. Divers with mobility difficulties at the surface tend to favor the jacket for its greater peripheral buoyancy.