Equip your semi truck to be Ready for the Road Ahead with the Buyers 18" x 18" x 36" Steel Underbody Truck Box, a key piece that offers increased storage space. By utilizing a secure design, this replacement box is able to offer an additional space to store tools, equipment, backup materials, and important items. Built with a weather-resistant and durable body to withstand extreme conditions. FleetPride is your First Click in Heavy Duty .