a system for assisting a distressed diver in order to communicate with the surface includes a housing that includes a portion containing a gas canister and an upper portion that is in fluid contact with an expandable balloon . by manipulating the upper portion , a needle or other activation mechanism dispenses the gas in the canister and allows the balloon to inflate . the housing is lifted by the balloon to the surface and is attached to a lockable spool reel tethered to the diver . the balloon may be also inflated for other uses in buoyancy , notification , and to frighten potentially dangerous threats when the spool reel is locked at an appropriate depth .