Shop for Aftermarket Sterling Acterra Fender Extensions. Upgrade your truck with durable, stylish fender extensions made for Sterling Acterra and AT9500 models: What 's Available: Steel extensions, multiple finishes, and customizable designs. Why Get Them: Boost style, improve aerodynamics, and protect your truck 's exterior. High-Quality Build: Built tough to handle the demands of the road. Whether it 's for a fresh look or added functionality, this lineup has the fender extensions you need.