This set of flatbeds is designed to replicate the type oftentimes seen on the roads hauling produce or other goods. They are 28' long, with the outside frames. In addition to your wheels of choice, the center is slightly depressed so the buyer/builder will need to add thin wood to replicate the decking. It has passed the software checks for the frosted detail materials, but should there be a problem, contact me via the direct shapeways link or via email to modelmechanic@gmail.com