Bulk bags are filled through the top of the bag in various ways, depending on the needs of the user. Bulk bags come in several configurations each designed for the specific filling method used. Spout topbags are commonly used with bag filling machines and hopper applications. Duffle top bags are usually used when the filling method is not as controlled, such as using a shovel or skid steer, but product protection when transporting is still desired. Open top bags are similar in use to duffle tops, but offer no product protection for transport.