Our dryer balls are made of 100% New Zealand sheep wool. They come unscented, with a 1 oz bottle of skin safe, phthalate free fragrance oil. Use 3-4 drops of fragrance oil per ball when you start washing so that the oil has time to soak in. Re-scent dryer balls every 3-4 washes. Dryer balls need to be washed (in a pillowcase, sock or mesh bag) approximately every 100 washes. Use 3 (or more, if extra large loads) per load. Dryer balls remove the need for fabric softener and decrease drying time, saving you money and energy! If you would prefer your dryer ball fragrance oil in a different scent, please reach out to us. We have hundreds of skin safe oils that can be used!