détendeur de secours
/byʁˈo də- lyʁʒɑ̃tˈist/
n
English: emergency regulator · 备用呼吸调节器
Sens：Regulator second stage that is connected by a hose to the regulator first stage; it is used to supply air to a diver in difficulty.
English: emergency regulator · 备用呼吸调节器