This unit started life as a Trane 50 ton RTU. It was given to the current owners of it after a remodel. The company that built and uses this porta cool did a good job on it. The heating portion was chopped out so it's a lot shorter. Blower and evap were reconfigured and the four ports were added on for flex hoses(four more directly opposite) We gave it a checkup and its in great shape. They use to rent a 20 ton portable and that did not cut it so they went big and creative. It was actually cheaper upgrading electrical services and constructing than to buy their own 20ton. Let me tell you though... it is no fun rolling up a 100' cord for a 3phase 50 ton unit. Also I don't think Trane stocks tires or wheel bearings.