The tumble dryer balls are balls made of 100% organic wool from Nepal. It’s a smart, cost-effective and sustainable solution to tumble dry your linen bedding (and your other laundry). It makes your laundry wonderfully soft, a liquid fabric softener (environmentally harmful) is no longer necessary. In addition, your laundry will dry faster, which saves you approximately 10 to 30% in time. The dryer balls last no less than 3 to 5 years.