Assertion: diver's volume | /r/CapableOf | get low
Facets:
Source sentences:
text: In some early oxygen rebreathers the diver had to manually open and close the valve to the oxygen cylinder to refill the counter-lung each time the volume got low.
text: In some early oxygen rebreathers the user had to manually open and close the valve to the oxygen cylinder to refill the counterlung each time the volume got low.