Oklahoma Joe's Charcoal/LP Gas/Smoker Combo 1,060 total square inch cooking surface 750 square inch primary cooking surface in main chamber over porcelain-coated cast iron grates. Number of grates: 6 310 square inch cooking surface in firebox chamber 3x 12,000 BTU Burners, (36,000 BTU's total) in gas grilling chamber 12,000 BTU side burner accommodates charcoal chimney starter