The Propex HS2211 exterior-mount propane heater offers 6,500 BTUs/Hr of heating capability directly into the cab. Combustion takes place outside of the cab which means no carbon monoxide is released inside (safe) and no moisture is added to the ambient air (dry heat). A digital LCD thermostat controls the temperature and blower fan speed, allowing for a “set it and forget it” experience – perfect for chilly nights.