1.Material:Aluminium 2.Positive pressure.0 to 3inHg;negative pressure.0 to -1inHg 3.Many jonits and tubes are included 1.Aluminium cylinder and cylinder head.2.Replaceable cylinder head O-rings,rubber piston ring and valves.3.The body is the switch to control two kinds of pressure conditions. Pressure range:positive pressure.0 to 3inHg;negative pressure.0 to -1inHg.4.The pressure gauge is ...