it might be a Lippert 1621HD. It should be the same one my Big Horn came with. I replaced mine with a TrailAir Flex Air pin box. I wanted to reduce the chucking like the MOR/ryde and stop the pounding that the front frames get through the king pin. It really does the job. The front of the fiver floats. Call Heartland with you VIN number and they have access to the parts list to your rig. They can tell you for sure. Several people like me have had the fasteners that hold the front frames together shear. Not a fun problem to have.