outward coil brush, also known as a spiral wound coil brush or open wound cylinder brush, is a type of cylindrical brush where the bristles extend outwards from a central core. It's created by winding a metal channel (typically with bristles attached) into a spiral or coil shape. These brushes are commonly used for cleaning, deburring, polishing, and other surface treatment applications. 

Cylindrical coil brushes might be seen on vacuum cleaners, street sweepers or an industrial compound applicator. Also called a shaft cleaning brush, a cylindrical coil brush is a long strip brush wound in a helical fashion to create a cylinder. These can be near any diameter and length, depending on the job they need to perform. Further, some of these internal cylindrical coil brushes or shaft cleaning brushes can be closely wound so that they appear as solid cylinders. Others may  have spaces between winds depending on the task at hand.