ARO PRO Series 1 1/2" Ported Metallic Diaphragm Pump, 90 GPM (340.7 LPM) flow. Mobility - Compact, rugged design allows for easy mobility. Efficiency - Motor design delivers optimum air efficiency. Reliability - ARO's patented 'Unbalanced' air valve ensures no-stall operation. Versatility - Available in aluminum, cast iron or stainless steel to withstand tough chemical applications. Environmentally Sound - Bolted construction for leak-free fluid handling. Serviceability - Easy access to ball checks and fluid caps for maintenance and repairs. Pump Casing Materials: Aluminum, Cast Iron & Stainless Steel. Diaphragm Materials: Viton, PTFE w/ Santoprene backer, Hytrel, Santoprene, Nitrile, Neoprene & E.P.R.