A measure of central nervous system oxygen toxicity caused by exposure to increased partial pressure of oxygen (PO2) while diving.

A diving mode used for dives performed with a rebreather that recirculates exhaled gas and removes carbon dioxide.

The greatest depth at which a breathing gas can be used before the partial pressure of oxygen (PO2) exceeds the safe limit.

A dive that does not require decompression time while ascending to the surface.

A measure of pulmonary oxygen toxicity caused by exposure to increased partial pressure of oxygen (PO2) while diving. One OTU is equivalent to breathing 100% oxygen at 1 ATM for 1 minute.

The pressure of the oxygen in the breathing gas, based on depth and oxygen percentage.

The amount of time that has elapsed since the completion of the last dive.

The estimated amount of time it will take to ascend to the surface, including decompression and safety stops.