Applications Used for pneumatic systems Compressors,compressed air system Suitable for fluid medium which does not clog connection port or corrode copper alloy. Case:Black Steel Ring:No Window:Acrylic Socket & Connection:Brass Movement:Brass Bourdon Tube:Copper alloy Pointer and Dial:Aluminum Range:Vacuum,compound 0 to 6000 psi Class:1.6% Mounting Type:Back