The additional blower that makes the hot air flow more quickly into the cab. Fits under the cab floor inside the front belly pan. The outlet is a little misshapen by the tightening of the jubilee clip. Worked great but as I am converting to diesel water cooled no longer required. £54.00 posted. I have some flexi hose that I will send down with it. Please see additional photo of the vans new heater for an example of the hose.