Our updated WTX-D twin cylinder wings are designed for twin set diving and perfectly complement the Apeks range of twin manifolds and the Tek3 regulators. Often referred to as donuts, the WTX-D wings are oval shaped air cells or bladders that are not permanently attached to a harness. Not only are these donut wings streamlined, but due to their shape being a continuous loop, they are very stable underwater. There is no dramatic shift of air from left to right.