This type of blender is a u-shaped trough with a horizontal agitator inside. These machines have ribbons, ribbons and paddles, or paddles only. Ribbon blenders can have one or two ribbons on the same shaft, or two ribboned shafts next to each other. Some ribbon blenders have a double helix design, while others have a ribbon oriented in different directions on the same shaft, allowing the ribbons to push the products two different ways to mix them. Some blenders have release valves under the trough while some troughs tilt to dump their contents. Ribbon carbon blenders are commonly used for for mixing dry powders, and mixing liquids into a dry mixture. Ribbon blenders are one of the slowest types of mixers, working slowly to create a consistent product.