Custom Truck Tarps for a Variety of Uses, Hopper Augers, Electric Combine Hopper Covers Michels Industries manufactured its first custom truck tarp back in 1969. Since then their line of custom truck tarps has expanded to include Side Rolling (PVC) and Gravel Body systems (Mesh,PVC,Neoprene,Canvas), Electric Grain Body, Gravel Body and Potato Bed systems. In addition to truck tarp systems, Michels has developed a hopper auger system to aide in unloading semi trailers.