Investors interested in stocks from the Manufacturing - Electronics sector have probably already heard of EnerSys (ENS) and Emerson Electric (EMR). But which of these two companies is the best option for those looking for undervalued stocks? Let's take a closer look.The best way to find great value stocks is to pair a strong Zacks Rank with an impressive grade in the Value category of our Style Scores system. The proven Zacks Rank emphasizes companies with positive estimate revision trends, and our Style Scores highlight stocks with specific traits.EnerSys and Emerson Electric are sporting Zacks Ranks of #2 (Buy) and #4 (Sell), respectively, right now. The Zacks Rank favors stocks that have recently seen positive revisions to their earnings estimates, so investors should rest assured that ENS has an improving earnings outlook. But this is just one piece of the puzzle for value investors.Value investors are also interested in a number of tried-and-true valuation metrics that help show when a company is undervalued at its current share price levels.Our Value category highlights undervalued companies by looking at a variety of key metrics, including the popular P/E ratio, as well as the P/S ratio, earnings yield, cash flow per share, and a variety of other fundamentals that have been used by value investors for years.ENS currently has a forward P/E ratio of 14.83, while EMR has a forward P/E of 16.50. We also note that ENS has a PEG ratio of 1.48. This figure is similar to the commonly-used P/E ratio, with the PEG ratio also factoring in a company's expected earnings growth rate. EMR currently has a PEG ratio of 1.86.Another notable valuation metric for ENS is its P/B ratio of 2.67. Investors use the P/B ratio to look at a stock's market value versus its book value, which is defined as total assets minus total liabilities. By comparison, EMR has a P/B of 4.23.Based on these metrics and many more, ENS holds a Value grade of A, while EMR has a Value grade of C.ENS has seen stronger estimate revision activity and sports more attractive valuation metrics than EMR, so it seems like value investors will conclude that ENS is the superior option right now.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 Enersys (ENS): Free Stock Analysis Report Emerson Electric Co. (EMR): Free Stock Analysis Report To read this article on Zacks.com click here.