Downy Unstopables in-wash scent boosters are small laundry scent beads that work inside your washing machine. Add them to each load of laundry to freshen your laundry and fabrics. It's easy to add long-lasting freshness to every load of laundry. First, shake a little or a lot of Downy Unstopables In-Wash Scent Booster into the cap. Toss into the washer drum at the beginning of the wash. Then, add your clothes, laundry detergent, and fabric softener. And that's it. Long-lasting freshness for up to 12 weeks really is that simple.