The Rasmussen 33" Natural Vented Uniform FireBalls - FB33-NA bring a clean and minimalist design to your fireplace. Made from durable ceramic with a natural tan-gray, heat-resistant stain, these fireballs are built to endure high temperatures without losing their color. Their uniform shape conceals the burner, creating a sleek and contemporary look. These fireballs are designed for use with the CS33W Burner (sold separately) to ensure optimal performance and a perfect fit.