"Anti-Static Dryer Balls" The secret's in the "bumps." These dryer balls soften fabrics without chemical softeners or dryer sheets (which I am allergic to). Tumbling in the dryer, they lift & separate fabrics to reduce drying time by up to 25%. The all over bumps make the fabric softer. Molded PVC. Set of 2. 3" diameter. These really work well. $9.99 for a pair.