Wing BCD

A wing BCD stores all the air on the back of the jacket. This means that you won't feel the pressure increasing around your waist when inflating the BCD. Just as a traditional BCD or a semi-wing a wing also offers a plate and strap on the back to fix your cylinder and metal D-rings to attach accessories or other parts like the octopus and second stage of your regulator.

^{Note: Both images are not from the same model BCD.}