The Trans/Air RT135 roof top ducted air system is designed for the transit, commercial bus, and limousine coach markets. With an IMACA capacity rating of 152K Btu/Hr, the RT135 is a perfect match for body lengths of 33-feet and up (up to 35 passengers) mounted on the Ford F650/750, IC TC, or Freightliner M2 or S2C chassis.