Rotary Vane Pumps with Manual Nozzle, 20 gpm, Rotary Vane Amp no checkout torsion resistant design Heavy duty construction Blade hooks torsion resistant design Heavy duty construction Blade hooks firmly to allow one person to measure easily and accurately and other hot metal surfaces Durable marks will not run Their rugged motors are explosion proof and rain proof to ensure a long life of dependability Heavy duty cast iron construction Carbon vanes and ceramic carbon seals reduce wear and repair expense Integral check valve with pressure relief on outlet side reduces pressure drop and improves vertical lift Self priming