For those looking for a good heat source for an argo or mule with cab,or a perhaps a tractor etc these look interesting.can be used to heat air or engine coolant.can use thermostat, timer, switch, remotestart,to run it. These heaters have their own pump and connect to the existing fuel tank on the vehicule.They burn diesel or gasoline,and have a built in fan.Check them out. WWW.espar.com I`m waiting for an e-mail about pricing will post later.Loaded with safety features too.