ProShares has launched its third inverse exchange-traded fund designed to short longer-term Treasuries.

The ProShares Short 20+ Year Treasury (NYSEArca:TBF - News) is expected to charge an annual expense ratio of 0.95.

Along with a pair offered by rival Direxion, the new offering represents the fifth ETF on the market taking short positions in the typically highly liquid government-backed fixed-income market.

But the newest is different from the rest. It offers less juice than others already on the market.

TBF seeks to provide 100% inverse exposure to the daily performance of its underlying Barclays Capital index.

ProShares has two other inverse ETFs aimed at providing 200% inverse coverage:The UltraShort 7-10 Year Treasury (NYSEArca:PST - News) and the UltraShort 20+ Year Treasury (NYSEArca:TBT - News).

Direxion also has a pair of inverse Treasury ETFs:The Daily 10-Year Treasury Bear 3x Shares (NYSEArca:TYO - News) and the Daily 30-Year Treasury Bear 3x Shares (NYSEArca:TMV - News). Both provide 300% inverse exposure to their underlying indexes and charge expense ratios of 0.95% each.