I have a B2B and this is the heater that was in it.It's a MoPar Model 70 and they were usually found in cars. It does not have the fresh air hookups and simply recirculates cab air. There is a coolant shut-off valve on the back of the cylinder head and a reostat switch to control the fan. I believe, along with radios, the heaters were a dealer-stalled accessory. In the case of my truck, the dealer most-likey didn't have the correct heater (which I believe is a Model 60) in stock and instead installed one for a car. Mine is bigger than the correct truck heater and required cutting down the back of the glove box.