A compressed air source (65-125 PSI operating
  range) is all you need to operate the Grover
  automatic positive air charging, self-contained
  sealant gun. Its 14 cubic inch material chamber
  can be hand or power loaded with as much as
  12 oz. of many kinds of sealants and mastics.
  The entire unit is lightweight for easy hand-held
  operation, about 12 lbs for manual and about
  14 lbs for automatic.

  Specifications:
  • 3" Air motor - 1 3/4" stroke
  • 70 to 1 pressure ratio
  • Brass air cylinder
  • Teflon coated material cylinder
  • Teflon material follower piston
  • Teflon pump rod cups
  • Injection nozzle .070 I.D. plated