The Double Header is a gas grill with four burners that are split between two different fireboxes, aka cooking spaces with their own lids. Each firebox has its own warming rack, too.
These two separate spaces give you a lot of versatility. Use only one firebox if you're cooking for a small crowd or use them both for a large group. This setup is also effective if you want to cook dishes in different temperature zones.
There's an additional burner on the side of the Double Header for smaller dishes.
These ribs cooked on the warming rack of one of the grill boxes while the burners were on low for three hours.