Rebreathers cover a range of equipment that has two common similarities.
- The exhaled gas is re-circulated within a breathing loop.
- The carbon dioxide is removed by an absorbent.
A rebreather is made up of an airtight breathing loop incorporating counter lungs—which allow gas to be moved around the breathing loop—breathing hoses, mouthpiece, oxygen-monitoring electronics, and an absorbent canister. The rebreather recirculates the breathing gas and adds oxygen as required. It is controlled by electronics that give various warnings if there is a problem with the rebreather. Your rebreather buddy will explain his or her particular unit and all the warning signals generated by the rebreather.
Unless ascending or completing minor breathing adjustments, rebreathers do not generally emit any bubbles from the unit. If they do, this could be a warning sign. You can learn more about rebreathers when you take additional training programs.