Metal cutting bandsaws are available in vertical and horizontal designs. Metal-cutting bandsaws are usually equipped with brushes or brushwheels to prevent chips from becoming stuck in between the blade's teeth. Horizontal bandsaws hold the workpiece stationary while the blade swings down through the cut. This configuration is used to cut long materials such as pipe or bar stock to length. The horizontal design is not useful for cutting curves or complicated shapes. Small horizontal bandsaws typically employ a gravity feed alone, retarded to an adjustable degree by a coil spring; on industrial models, the rate of descent is usually controlled by a hydraulic cylinder bleeding through an adjustable valve.