UWS Blue Series-Slim Line Box The UWS Slim Line Series was developed to fit the maximum amount of storage into many of the new shorter bed trucks. This box easily fits the limited space in the bed available in front of the wheel well. UWS designed this box with full size features much like a custom product made specifically for your truck. The UES lines are gaining popularity in Dallas, Rockwall, Mesquite, Garland, Rowlett, Greenville, Commerce, Sulphur Springs, and throughout the North Texas area.