I had originally puchased a pair of the DryerMax Dryer Balls, also available on Amazon. Mysteriously, one of the pair disappeared from the dryer (just like socks!), so I wanted to replace it. I didn't realize there were such strong differences between Dryer Balls offered on Amazon. When I ordered this pair, they were hard as rocks. When I started the dryer, the noise of the impacts was unacceptable. The DryerMax balls, on the other hand, are squishy.