Abstract: A device for heat exchange for use with underwater diving equipment including a pressurized gas source is disclosed. The heat exchange device includes a manifold and a heat sink. The manifold distributes gas supplied from the pressurized gas source to breathing equipment. The heat sink is for warming up the gas before the gas is distributed to the breathing equipment using heat exchange with ambient water surrounding the heat sink. The manifold and the heat sink are connected such that the gas warmed up by the heat sink returns to the manifold before being distributed to the breathing equipment. The returning warm gas may warm up the manifold and the cold gas entering the manifold.

Abstract: A buoyancy compensating device is disclosed. The buoyancy compensating device includes an air chamber for containing gas for controlling buoyancy, a vent valve for releasing the gas from the air chamber, a tube secured to a shoulder strap of the buoyancy compensating device, and a pull knob for operating the vent valve. The pull knob includes a head piece and an elongated tail piece extending from the head piece. The tail piece is extended into the tube and connected to the vent valve. The tail piece is configured to reside in the tube while the pull knob is pulled by the diver for opening the vent valve. The tail piece may be connected to a pull cord which is then connected to the vent valve. Alternatively, the tail piece may be directly connected to the vent valve.