The Rasmussen 21" Dark Gray Vented Uniform FireBalls - FB21-DG add a bold, modern aesthetic to your fireplace. Made from durable ceramic with a heat-resistant dark gray stain, these fireballs are designed to withstand high temperatures while maintaining their color. Their uniform shape helps conceal the burner, creating a sleek and minimalist look. These fireballs are perfect for vented fireplaces in both residential and commercial spaces, and they are compatible with Rasmussen Vented Custom Pan Burners (sold separately).