Fire Pit Rings are the quickest and most economical way to build a fire pit. 3/8 inch stainless steel pipe construction with punched (not drilled) ports. The ring has a 1/2 inch female pipe connection. BTU output is determined by the supply line size and the distance of the supply line run. Double ring burner. Can be used with natural gas and propane. Fire pit ring only. This ring is not UL approved for outdoor use. Flame height is directly related to the BTU output of the unit. For maximum flame height, allow for 400,000 BTUs.