The MacNaught Max Flow M-DDP38VT-02 is a 1-1/2" carbon-filled PVDF AODD (air-operated double-diaphragm) pump for chemical duty. Compressed air drives two diaphragms back and forth to move liquid. Cal West Mashy represents MacNaught AODD and oil transfer pumps for Northern California and Western Nevada. Call 888-841-3335.