Double heater for mount on top of propane tank. 30k BTU provides exceptional heat, enough to take the chill out of a two car garage. Both sides can be used for double heat or only one side for single heat to save gas. The heater includes a tip switch to turn it off if it falls over and a thermocouple safety which shuts off gas flow if the flame blows out. Approximate 15 hour run time on a full twenty pound tank.