Helium Sensor – Blind Plug This item can be used as a substitution for a Helium sensor in case the Helium sensor is not required to be used by the diver. In case of using this device, Helium sensor must be turned off in user menu according to our instructional video below. INSTALATION TUTORIAL VIDEO IMPORTANT: Liberty unit mustn’t be used without either Blind Plug or Helium sensor in its place.