September began just how August ended, with just a single exchange-traded product coming to market — and again, this one’s a doozy.

Royal Bank of Scotland’s (NYSE:RBS) US Large Cap Alternator Index ETN (NYSE:ATLT) is an exchange-traded note that seeks exposure to the RBS US Large Cap Alternator Index — an index that, depending on its proprietary blend of herbs ‘n’ spices, will give investors exposure to one of three benchmarks: the S&P 500 Total Return Index, the S&P 500 Low Volatility Total Return Index or the S&P 500 Equal Weight Total Return Index.

Which index ATLT guns for is decided by a “relative strength score.” Every month the indices are each ranked by their average historical returns, then the Alternator Index issues a relative strength score for those indices for their prior one-month, three-month, six-month, nine-month and 12-month periods. The index with the highest score is the one the ATLT tracks.

RBS touts ATLT as a way to get constant large-cap equity exposure that’s re-tuned monthly to the current market cycle. For example, having exposure to the Low Volatility Total Return Index would be ideal during shakier times, but a switch to the more small-cap-exposed Equal Weight would be beneficial in the start of a bull charge.

The RBS US Large Cap Alternator Index ETN charges a hefty 1% in fees and is starting with about $4 million in assets.

The previous week saw an S&P 500 ETF with volatility hedging come to market. In all, 141 new funds have come out so far in 2012, according to XTF.com.

Kyle Woodley is the assistant editor of InvestorPlace.com. As of this writing, he did not hold a position in any of the aforementioned securities. Follow him on Twitter at @KyleWoodley.