Keep your EGG performing as it should with the Big Green Egg Fire Box MX. Designed as a replacement ceramic fire box for the Big Green Egg MiniMax, it sits inside the ceramic base and holds the charcoal while helping manage airflow through its built-in openings. That airflow is key to maintaining steady temperatures and reliable cooking performance. Made from Big Green Egg’s high-quality ceramic, it supports excellent heat retention for grilling, roasting, baking and low-and-slow cooking.