If you're interested in broad exposure to the Mid Cap Blend segment of the US equity market, look no further than the Vanguard MidCap ETF (VO), a passively managed exchange traded fund launched on 01/26/2004.The fund is sponsored by Vanguard. It has amassed assets over $56.78 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. Thus, companies that fall under this category provide a stable and growth-heavy investment.Blend ETFs usually hold a mix of growth and value stocks as well as stocks that exhibit both value and growth characteristics.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 0.04%, making it the least expensive products in the space.It has a 12-month trailing dividend yield of 1.12%.Sector Exposure and Top HoldingsEven though ETFs offer diversified exposure which minimizes single stock risk, it is still important to look into a fund's holdings before investing. Luckily, 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 22.30% of the portfolio. Industrials and Healthcare round out the top three.Looking at individual holdings, Dexcom Inc. (DXCM) accounts for about 0.77% of total assets, followed by Marvell Technology Inc. (MRVL) and Msci Inc. (MSCI).Performance and RiskVO seeks to match the performance of the CRSP US Mid Cap Index before fees and expenses. The CRSP US Mid Cap Index targets inclusion of the U.S. companies that fall between the top 70%-85% of investable market capitalization.The ETF has gained about 26.54% so far this year and is up roughly 24.95% in the last one year (as of 12/31/2021). In the past 52-week period, it has traded between $203.74 and $261.20.The ETF has a beta of 1.09 and standard deviation of 23.96% for the trailing three-year period, making it a medium risk choice in the space. With about 381 holdings, it effectively diversifies company-specific risk.AlternativesVanguard MidCap ETF holds a Zacks ETF Rank of 2 (Buy), which is based on expected asset class return, expense ratio, and momentum, among other factors. Because of this, VO is an outstanding option for investors seeking exposure to the Style Box - Mid Cap Blend segment of the market. There are other additional ETFs in the space that investors could consider as well.The iShares Russell MidCap ETF (IWR) and the iShares Core S&P MidCap ETF (IJH) track a similar index. While iShares Russell MidCap ETF has $31.62 billion in assets, iShares Core S&P MidCap ETF has $68.21 billion. IWR has an expense ratio of 0.19% 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 Vanguard MidCap ETF (VO): ETF Research Reports DexCom, Inc. (DXCM): Free Stock Analysis Report Marvell Technology, Inc. (MRVL): Free Stock Analysis Report MSCI Inc (MSCI): Free Stock Analysis Report iShares Core S&P MidCap ETF (IJH): ETF Research Reports iShares Russell MidCap ETF (IWR): ETF Research Reports To read this article on Zacks.com click here.