The iShares Russell MidCap ETF (IWR) was launched on 07/17/2001, and is a passively managed exchange traded fund designed to offer broad exposure to the Mid Cap Blend segment of the US equity market.The fund is sponsored by Blackrock. It has amassed assets over $27.10 billion, making it one of the largest ETFs attempting to match the Mid Cap Blend segment of the US equity market.Why Mid Cap BlendWith market capitalization between $2 billion and $10 billion, mid cap companies usually contain higher growth prospects than large cap companies, and are considered less risky than their small cap counterparts. These types of companies, then, have a good balance of stability and growth potential.Blend ETFs are aptly named, since they tend to hold a mix of growth and value stocks, as well as show characteristics of both kinds of equities.CostsWhen considering an ETF's total return, expense ratios are an important factor, and cheaper funds can significantly outperform their more expensive counterparts in the long term if all other factors remain equal.Annual operating expenses for this ETF are 0.18%, putting it on par with most peer products in the space.It has a 12-month trailing dividend yield of 1.38%.Sector Exposure and Top HoldingsWhile ETFs offer diversified exposure, which minimizes single stock risk, a deep look into a fund's holdings is a valuable exercise. And, most ETFs are very transparent products that disclose their holdings on a daily basis.This ETF has heaviest allocation to the Information Technology sector--about 16.80% of the portfolio. Industrials and Financials round out the top three.Looking at individual holdings, Synopsys Inc (SNPS) accounts for about 0.51% of total assets, followed by Autozone Inc (AZO) and Cadence Design Systems Inc (CDNS).The top 10 holdings account for about 4.38% of total assets under management.Performance and RiskIWR seeks to match the performance of the Russell MidCap Index before fees and expenses. The Russell Midcap Index measures the performance of the mid-capitalization sector of the U.S. equity market.The ETF has lost about -16.90% so far this year and is down about -14.17% in the last one year (as of 09/20/2022). In the past 52-week period, it has traded between $62.75 and $85.28.The ETF has a beta of 1.08 and standard deviation of 26.50% for the trailing three-year period, making it a medium risk choice in the space. With about 834 holdings, it effectively diversifies company-specific risk.AlternativesIShares Russell MidCap ETF carries a Zacks ETF Rank of 3 (Hold), which is based on expected asset class return, expense ratio, and momentum, among other factors. Thus, IWR is a sufficient option for those seeking exposure to the Style Box - Mid Cap Blend area of the market. Investors might also want to consider some other ETF options in the space.The Vanguard MidCap ETF (VO) and the iShares Core S&P MidCap ETF (IJH) track a similar index. While Vanguard MidCap ETF has $49.47 billion in assets, iShares Core S&P MidCap ETF has $60.55 billion. VO has an expense ratio of 0.04% and IJH charges 0.05%.Bottom-LineRetail and institutional investors increasingly turn to passively managed ETFs because they offer low costs, transparency, flexibility, and tax efficiency; these kind of funds are also excellent vehicles for long term investors.To learn more about this product and other ETFs, screen for products that match your investment objectives and read articles on latest developments in the ETF investing universe, please visit Zacks ETF Center. Want key ETF info delivered straight to your inbox? Zacks’ free Fund Newsletter will brief you on top news and analysis, as well as top-performing ETFs, each week.Get it free >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report iShares Russell MidCap ETF (IWR): ETF Research Reports AutoZone, Inc. (AZO): Free Stock Analysis Report Synopsys, Inc. (SNPS): Free Stock Analysis Report Cadence Design Systems, Inc. (CDNS): Free Stock Analysis Report iShares Core S&P MidCap ETF (IJH): ETF Research Reports Vanguard MidCap ETF (VO): ETF Research Reports To read this article on Zacks.com click here. Zacks Investment Research