2X funds see also www.profunds.com. Their funds cover more areas you can go short on than Rydex and sometimes have a larger leverage. Also be aware that 'some' brokers charge 'fast trading fees' for funds sold before 180 days have passed.
I use brownco which does 'not' do that.
Take Care, Steve
You CAN time the market!
But only after you trash the big 3 myths.
Myth 1 - its possible to get every point of every move ...Myth 2 - you'll never have a drawdown ......Myth 3 - you'll never have a loss