Sheet systems are commonly used for uneven loads, bagged products or even fragile cargo. The sheet system contains ratchet straps at evenly spaced intervals along the length of the sheet.
If you experience loads with varying height, extra sheet can be added to accommodate for the drop and gain in height over the length of the vehicle. When loading an even load, the extra sheet and straps can be simply stored at the end of the vehicle without any obstruction or interference.
Sheets can be manufactured to any configuration, often operators have a two or three sheet combination within the vehicle.