Work of breathing depicts the cycle of inhalation and exhalation energy expended to breathe from a regulator.
Inhalation is the effort to open valve and maintain airflow.
Exhalation is the effort to push exhaled breath through the regulator casing and past the exhaust valve.
So, the lower the better. SCUBAPRO regulators exceed WOB standards of both the US Navy and European CE.
EN250 standards for a cold water regulator mandate a limit of
3.0 Joules per Liter
at a depth of 50m, with 300bar of tank pressure, 2° to 4° C water temperature and
25 breaths per minute.