... 2.piston compressor 3.3 cylinder compressor 4.oilless air oil free air compressor piston 4kw WW5512 : Feature:1.smart,and ... light weight3.low cost,low air consumption4.electric save,oil save,electric save.5.air compressor used in food, ... cooling air,reducin displacement temp. quickly.3.cylinder cover:Adopt aluminium alloy material,increasing air displacement.Photos: oil free air compressor piston ...