Underwater Diving

Breathing systems consist of one or more diving cylinders containing breathing gas at high pressure connected to a diving regulator.
• Rebreather sets
Closed-circuit breathing systems allow recycling of exhaled gases. This reduces the volume of gas used, making a rebreather lighter and more compact than an open-circuit breathing set. Rebreathers also make far fewer bubbles and less noise than open-circuit scuba; this makes them attractive to military, scientific and media divers.