There are 2 distinct types of LTL Controls 4 Burner CO2 Generators available:  Propane and Natural Gas.

You can then choose between High Altitude (above 5,000 ft) and Low Altitude (below 5,000 ft) models of each.

All generators come with the correct regulator and hose, along with pre-installed, clean-burning brass burners. Both units are equipped with features like a safety tip-over switch, which automatically turns off the unit if it tips over or falls, an electronic ignition with dual redundant solenoid valves, which eliminates the open pilot flame and makes these generators twice as safe as others on the market. 

Cubic Feet CO2 Per Hour: 11