43.12.00 Gas Compressors
43.12.57 Rotary Scroll Compressors
43.12.11 Centrifugal Compressors 43.12.13 Diagonal or Mixed-flow Compressors 43.12.16 Axial-flow Compressors 43.12.33 Single-acting Reciprocating Compressors 43.12.34 Double-acting Reciprocating Compressors 43.12.37 Diaphragm Reciprocating Compressors 43.12.51 Rotary Screw Compressors 43.12.53 Rotary Vane Compressors 43.12.56 Rotary Liquid-ring Compressors 43.12.57 Rotary Scroll Compressors