Investors interested in stocks from the Manufacturing - General Industrial sector have probably already heard of Barnes Group (B) and Ingersoll-Rand (IR). But which of these two companies is the best option for those looking for undervalued stocks? Let's take a closer look.We have found that the best way to discover great value opportunities is to pair a strong Zacks Rank with a great grade in the Value category of our Style Scores system. The proven Zacks Rank puts an emphasis on earnings estimates and estimate revisions, while our Style Scores work to identify stocks with specific traits.Right now, Barnes Group is sporting a Zacks Rank of #2 (Buy), while Ingersoll-Rand has a Zacks Rank of #3 (Hold). This means that B's earnings estimate revision activity has been more impressive, so investors should feel comfortable with its improving analyst outlook. But this is just one factor that value investors are interested in.Value investors also try to analyze a wide range of traditional figures and metrics to help determine whether 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.B currently has a forward P/E ratio of 19.33, while IR has a forward P/E of 20.86. We also note that B has a PEG ratio of 1.93. 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. IR currently has a PEG ratio of 1.95.Another notable valuation metric for B is its P/B ratio of 2.58. The P/B is a method of comparing a stock's market value to its book value, which is defined as total assets minus total liabilities. By comparison, IR has a P/B of 4.40.Based on these metrics and many more, B holds a Value grade of B, while IR has a Value grade of C.B has seen stronger estimate revision activity and sports more attractive valuation metrics than IR, so it seems like value investors will conclude that B 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 Barnes Group, Inc. (B): Free Stock Analysis Report Ingersoll-Rand PLC (Ireland) (IR): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research