For many of you who make your living out on the job site a pickup tool box is necessity. Let’s now cover how choose the right one for your truck. Top Mounted Truck Bed Tool Boxes These are the compartments you see on welding trucks, plumbing trucks, and utility service trucks. They’re mounted up above the bed rails and have “cabinet” style doors for storing tools. These are great if your truck is used full time for work and you absolutely must have a maximum amount of storage space. Measuring Your Truck Bed To make sure that the toolbox you’re ordering will actually fit your truck bed, .