With two, 4-gallon buckets in place.
See comparison chart of full size packs.
The Wrangler offers flat-bottomed side pockets with a bungee cord around the top of the open pockets to make sure your gear stays in place. The zippered pockets feature double zippers so it can be opened at any point on the zipper. Each side pocket will hold two 1-liter Nalgene bottles side by side even with two square four-gallon plastic buckets in the main compartment.
The Wrangler Pack comes with a saddle, two detachable panniers, two mohair blend cinches (one 20" and one 16"), a chest plate, a belly strap, and a pair of top load straps. Standard Colors: red, forest green, royal blue, purple, navy, and, black. 4.68 cubic feet.