small propane bottle refilling

Had a friend who worked for a propane company. He had this rig that you could use to fill up the grill bottles from a big tank. He had a special tank on the truck that sucked from the bottom to get liquid. If not you have to flip the tank over.
One of these days I need to make up one of those hoses.
What are you refilling, those little coleman bottles? Thats the only adapters I have ran across for sale.