... extended tosuit application requirements. SpecificationsType of gas: Natural gas, propane, propane/butane, butane, town gas, coke oven gas, other gases on requestFlame shapes: Normal ... equipped with a built-in limiting orifice valve for gas flow adjustment,gas metering orifice for set-up and tuning, and ... steel tube extensions for indirect firing Burners BIO series for Boiler/Gas stove /Furnace