A 1/2" Undermount Spring Assembly with Drop Plate for the drvers side of Aero Industries Easy Cover tarp systems. This crucial component helps power the automated tarping mechanism on dump trucks and trailers. It's designed for Easy Cover systems typically used on bodies between 10 and 17 feet long. Essentially, this spring assembly provides the necessary tension for the tarp to extend and retract smoothly. It's a key piece for maintaining efficient and reliable tarp operation on the road.