Propex HS2000 Heater. Fueled by either propane or butane, this. 4.5kg butane 31.7 hours. 15kg butane 105.6 hours. 19kg butane 133.8 hours. 12v & LPG or 24v & LPG. 3.9kg propane cylinder will last - 27.5 hours.
eBay