ProShares Ultra Bloomberg Natural Gas 2x Shares 

The fund seeks to meet its investment objective by investing normally in Natural Gas futures contracts. It may also invest in swaps if the market for a specific futures contract experiences emergencies (e.g., natural disaster, terrorist attack, or an act of God) or disruptions (e.g., a trading halt or a flash crash) or in situations where the Sponsor deems it impractical or inadvisable to buy or sell futures contracts (such as during periods of market volatility or illiquidity).