Upgrade your Peterbilt 379 or 389 with the Replacement Battery Box Lid with Top Step. Made of durable aluminum, this lid is 31 1/2 inches wide by 13 inches deep and fits most models of these trucks. Sold individually, this lid is a practical and functional addition to your vehicle, providing easy access to the battery box while adding a convenient top step for accessibility. Improve the practicality and functionality of your truck with this replacement lid.