a fundamentally different kind of diving apparatus
a SCUBA device that allows you to breathe your own air over and over again and produce no bubbles
a self-contained breathing apparatus for use underwater which reuses at least part of each breath
a type of breathing equipment that
an underwater breathing system that recycles air; divers inhale air from a tank and exhale air into a machine that recycles the air and makes it available for the diver again; used for longer and deeper research and military dives
Device that reuses air by scrubbing or removing the carbon dioxide from it and adding used oxygen. Alternative to SCUBA generally loved by all tekkies - see tekkies.
A rebreather is a type of breathing set that provides a breathing gas containing oxygen and recycles exhaled gas. This recycling reduces the volume of breathing gas used, making a rebreather lighter and more compact than an open-circuit breathing set for long durations in environments where humans cannot safely breathe from the atmosphere. In the armed forces it is sometimes called "CCUBA" (Closed Circuit Underwater Breathing Apparatus).