Nellie’s newest addition to the dryer ball family is made of 100% pure New Zealand wool. The dryer balls come in a reusable tin that doubles as a piggy bank, that way you have a place to save the money from using less energy drying. Toss 4 dryer balls into the dryer to reduce drying time, soften fabrics and reduce wrinkles. All without the use of any chemicals. Separate natural fabrics from synthetic fabrics to help reduce static.