Flatbed

An open, level trailer with no sides or roof, loaded from any side or above.

A flatbed is a flat, open platform trailer with no walls or roof, so freight can be loaded from the sides, rear, or top by crane or forklift. It's the most common trailer for building materials, machinery, and anything that doesn't fit a dry van. Standard deck height makes tall loads go over-height sooner than a step deck or double drop.