This Bunsen Burner is a high-quality, American-made burner with a nickel-plated, die-cast zinc base. Burners feature aluminum mixing tubes and serrated gas inlet connections. *Note: CFHs and BTU Outputs are figured on: 5 inch water column pressures for artificial and natural burners. 11 inch water column pressures for LP burners. Inlet OD for all burners: 5/16" and serrated