Rasmussen 20" Light Gray Alterna Ventless FireStones Single Sided - AFS20-LG adds a contemporary touch to your ventless fireplace with its soft, light gray hue. Crafted from durable ceramic-bonded refractory material, these firestones offer high-temperature resistance, ensuring long-lasting beauty without cracking or popping. Designed to elegantly conceal burners, this set enhances any transitional living space and is compatible exclusively with Rasmussen Alterna Vent-Free FireStones Burners (sold separately).