This ETF offers exposure to small and mid-cap equities in the U.S. market, thereby delivering a way to access an asset class that is often overlooked by many investors. PRFZ is linked to a RAFI-weighted index which selects holdings based on the following four fundamental measures of size: book value, cash flow, sales and dividends. Mid and small caps can offer a unique risk/return profile, delivering increased sensitivity to local consumption and exposure that some consider to be more reflective of the local economy. As such PRFZ can be appealing to those looking to construct a long-term portfolio with well-rounded exposure, by serving as a great complement to more popular large-cap heavy ETFs. Other alternatives within this category include the equal-weighted EWRS or the more liquid IWM. PRFZ is also considerably more expensive than VTWO, but for investors who believe in the merits of the RAFI methodology it may be a better way to achieve emerging markets exposure.