Like the air from a scuba tank! Wonder if anyone knows Dave and could suggest it to him? Ray McAllister, Prof (Emeritus) Ocean Eng., FAU, Boca Raton, FL 33064 Diving Dinosaur, Geologist/Oceanographer/Ocean Engineer, 44 years SCUBA mcallist@gate.net (954) 426-0808, Author Diving Locations, Boynton/Dania