HiBlow 40 Septic Linear Air Pump (Longest Lasting Pump on The Market) w/Back Pressure Safety Valve NSF Approved For Most Residential Sewer Treatment Plants ("Blue Diamond" is Not) Longest Lasting Septic Air Pump on the Market! Only Septic Air Pump on the Market Protected Against Aerator Pipe Obstructions Safety Valve Eliminates Premature Diaphragm Tears Safety Valve Eliminates Premature Air Pump Motor Overheating and Burn Out