The F31-1036ss-0 was created for those who purchased an upgrade kit for a 1995 – 2014 Kenworth and would like to replace the remainder of the box. This box would come with a gasket set, evaporator, heater core, freeze switch, and appropriate expansion valve. (We need to know the year of your truck to determine the correct expansion valve. Have questions? Call us at (616) 834-1503.