iShares U.S. Medical Devices ETF(AMEX:IHI)

IHI is a niche sector fund that specifically targets domestic companies engaged in the medical devices portion of the broader health care space. It aims to invest in companies that manufacture and distribute medical devices such as magnetic resonance imaging (MRI) scanners, prosthetics, pacemakers, X-Ray machines, and other non-disposable medical devices. The fund is rebalanced quarterly and weighted by float-adjusted market cap, subject to capping restraints of 22.5% for any individual company. The fund uses a sampling method, and may not hold all of the securities in the index.