Welcome to Zylstra Automotive and Diesel Performance web site. We offer a full line of diesel auxiliary fuel tank (Zylstra FuelBox a.k.a TheFuelBox) and toolbox combinations for Ford, Chevy and Dodge pickups. In addition to our premium line of auxiliary tank, We offer our award winning Automatic Fuel Transfer Controller (AFC) which electronically manages transfer between our auxiliary tanks and your trucks existing fuel tank.