Duralast batteries are made by:
Johnson Controls Inc. One of the few manufactures in world.
They make batteries for Interstate, Optima, Autozone (Duralast), Sears (Diehard), Bosch, Walmart in the Northern US (Everstart), and many OEM's.
Walmart batteries in the Southern US are typically made by Exide.
Excellent Batteries.
The other battery Manufactures are Exide, Panasonic, and Solite.