Oilfield service companies supply the products, services, and systems that enable major integrated, independent, and national oil companies to explore for petroleum reserves and complete and produce oil and gas wells. The major service companies typically market their services to the end-user on the basis of availability, performance, quality, reliability, technical support and service, and price. Like contract drilling, oilfield services is an intensely competitive and cyclical industry. Periods of flush demand, tight inventories, and strong pricing are followed by periods of weak demand, excess inventories, and cutthroat pricing. Although no one firm dominates the market, certain companies have or share dominant positions in specific applications, and several companies are distinguished by their ability to weather the industry's challenging fundamentals.