... carbon steel Type: 1.Standard model:single-stage compressor circuit2.Level control mode :multi-effect compressor circuit3.Row control mode: ... mode:double-stage compressor circuit5.Cross level control mode:four stage compressor circuit Bay numbers:2,3,4,5,6,8, ... of pplications such as:Window, Split and package AC systems;2.Commercial Refrigeration Systems (Kitchen refrigerator,bottle cooler,deep freezer, ...