Air Hydraulic Foot Pump  Built-in safety valve ensuring operating safety against overloading.  Models 2820 are designed to utilise exhaust air to help power the pump.  Gauge is oil filled to prohibit shock load damage and includes an external rubber guard for added protection. For light and corrosion free purposes The Air Cylinder and Piston are made from 6061-T6 Aluminium Alloy Air exhaust muffler for quieter operation. Air and oil inlet filters for reduced risk of damage from contamination.  All air pumps are designed to be used with single acting cylinders. Website:http://www.dudemachinery.com