I used to work for an equipment manufacturer, we made equipment for automotive battery plants. I traveled throughout the US installing this equipment and doing service work as well. Walmart, Kmart, Autozone, O'reilly's, etc. all went through the same process, Only difference was the color of the cases and/or tops. Interstate was made in a lot of the same plants, (never saw a plant owned by Interstate) only difference was the interstates had a better quality control plan, and they were charged in the water bath tables for a longer period of time...