Corner dual auger grain carts have a horizontal auger that runs the length of the cart to move grain toward the vertical auger. On a corner dual auger cart, the vertical auger tips forward and tips outward for a clear view of the spout. Models 1721, 1521, 1421, and 1321 have this design.
Dual auger grain carts also have a horizontal auger, but the vertical auger is tight against the grain tank and tips just out to the side. While the spout is not as easy to see, the overall length of the cart is shorter. They have a lower cost of ownership than the corner dual auger grain carts. Model 1121 has this design.
Single auger grain carts have just one auger that moves grain from the central sump of the grain tank, out through the side of the cart, and discharges it out the spout. They have a lower cost of ownership than dual auger carts. Model 1051 has this design.