 The need to remember the history of valve operation and the lack of facility to connect a redundant regulator made the use of independent twins the usual alternative.This also has limitations, even when the contents can be closely monitored by using submersible pressure gauges.In 1970 a group of divers including Tom Mount, Ike Ikehara and George Benjamin came up with the concept and had the first recorded dual outlet scuba valves prototyped.