The term 'Western Gas Brand' refers to two major gas companies in the western United States: Tesoro (6 letters) and ARCO (4 letters). Tesoro is an American Fortune 100 company that operates refineries, retail fuel stations, and convenience stores. ARCO is a subsidiary of BP and is one of the largest suppliers of gasoline in the western United States. Both companies are well-known for their competitive prices and quality service.