I use a 4 inch PVC sewer pipe. Round. Screw in caps both ends. U clamps from elect dept. Screwed to rails under RV right in front of the tires. All the way across from one side to the other. You can mount anywhere though according to where your slide outs are etc.
2015 338RETS Eagle Premier gloss sides., king.
2012 Ram 3500, crew cab 4x4 duelly Deleted
16k miles, 530HP, 1000 +torque.