HPC 18 Inch Natural Gas Fire Pit Kit With Square Stainless Steel Ring - Match Light. FPSSQ18 Kit. Fire Pit Kits. This HPC fire pit kit includes a 18 inch stainless steel square single ring burner with 1/2 inch gas hub, plumbing, fittings, valve, polished brass key with flange, and 50 pounds of lava rock. 150,000 BTUs. For use with natural gas only.