Assertion: diver's system | /r/AtLocation | common use
Facets:
value: for surface-supplied divers
type: PURPOSE
Source sentences:
text: This system was well-established by the mid-20th century, has been improved several times as new technology became available, and is still in common use for surface-supplied divers using lightweight demand helmets and full-face masks.
text: Two basic systems of attaching the helmet to the suit were in common use: