Rasmussen 24" Dark Gray Alterna Ventless FireStones Single Sided - AFS24-DG brings a bold, contemporary look to your ventless fireplace with its rich dark gray tone. Made from durable ceramic-bonded refractory material, these firestones resist high temperatures, ensuring lasting beauty without cracking. Ideal for concealing burners, this set adds a sleek, modern touch to any space. Exclusively compatible with Rasmussen Alterna Vent-Free FireStones Burners (sold separately).