ARO 2” Ported Metallic Flap Valve Pump – 172 GPM (651 LPM). Able to handle 2" semi-solids and 3/4' solid materials! Available in three different construction materials including Aluminum, Cast Iron or Stainless Steel with the option of Plated Steel or Stainless Steel hardware. Efficiency - Simul-Shift™ valve provides ultra-positive, reliable shift signal. Reliability - ARO's patented 'Unbalanced' air valve ensures no-stall operation. Pump Casing Materials: Aluminum, Cast Iron & Stainless Steel. Diaphragm Materials: Santoprene, Nitrile, PTFE w/ Santoprene backer & Viton.