The Bio Green Frost Buster 800w works with a small, thermally protected gas flame that produces both heat and carbon dioxide, both of which are need for healthy plant growth. The thermal protection makes for maximum safety in use and prevents any escape of unburnt gas. This heater is manually ignited, and then is switched off by turning the valve on the gas bottle off. It does not have a thermostatic control or adjustment of any kind, they are designed to provide a constant low level of heating to guard against frost in particular. The Frost Buster is 30% more economical than paraffin heaters, and includes both hose and regulator. Comes with 3 year manufacturer warranty. Frost protects greenhouses up to 8'x6'.