Investors looking for stocks in the Chemical - Specialty sector might want to consider either H. B. Fuller (FUL) or Ecolab (ECL). But which of these two companies is the best option for those looking for undervalued stocks? Let's take a closer look.Everyone has their own methods for finding great value opportunities, but our model includes pairing an impressive grade in the Value category of our Style Scores system with a strong Zacks Rank. The Zacks Rank favors stocks with strong earnings estimate revision trends, and our Style Scores highlight companies with specific traits.Currently, H. B. Fuller has a Zacks Rank of #2 (Buy), while Ecolab has a Zacks Rank of #5 (Strong Sell). This system places an emphasis on companies that have seen positive earnings estimate revisions, so investors should feel comfortable knowing that FUL is likely seeing its earnings outlook improve to a greater extent. But this is just one factor that value investors are interested in.Value investors also tend to look at a number of traditional, tried-and-true figures to help them find stocks that they believe are undervalued at their current share price levels.Our Value category grades stocks based on a number of key metrics, including the tried-and-true P/E ratio, the P/S ratio, earnings yield, and cash flow per share, as well as a variety of other fundamentals that value investors frequently use.FUL currently has a forward P/E ratio of 18.92, while ECL has a forward P/E of 49.39. We also note that FUL has a PEG ratio of 2.43. This popular metric is similar to the widely-known P/E ratio, with the difference being that the PEG ratio also takes into account the company's expected earnings growth rate. ECL currently has a PEG ratio of 4.93.Another notable valuation metric for FUL is its P/B ratio of 2.08. The P/B ratio is used to compare a stock's market value with its book value, which is defined as total assets minus total liabilities. For comparison, ECL has a P/B of 9.84.Based on these metrics and many more, FUL holds a Value grade of B, while ECL has a Value grade of F.FUL sticks out from ECL in both our Zacks Rank and Style Scores models, so value investors will likely feel that FUL is the better 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 H. B. Fuller Company (FUL): Free Stock Analysis Report Ecolab Inc. (ECL): Free Stock Analysis Report To read this article on Zacks.com click here.