I guess it comes standard on the Ram 2500 Power Wagon. The "spread sheet" doesn't show it as an extra option. It looks exactly like the Line-X used in the bed - EXCEPT - it doesn't have all those knobbies.
It's sprayed on good and thick on the underside. They knew what they were doing - both drive shafts were covered. Not a bit of the black stuff on either of them.
FWIW - I had the Line-X company in Spokane spray the complete underside of my TJ Jeep. The Line-X man said they under coat vehicles all the time. Pickups, trucks, and vehicles like Jeeps.