Investors with an interest in Building Products - Retail stocks have likely encountered both Tecnoglass (TGLS) and Fastenal (FAST). But which of these two stocks offers value investors a better bang for their buck right now? We'll need to 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 Zacks Rank is a proven strategy that targets companies with positive earnings estimate revision trends, while our Style Scores work to grade companies based on specific traits.Right now, Tecnoglass is sporting a Zacks Rank of #1 (Strong Buy), while Fastenal has a Zacks Rank of #2 (Buy). The Zacks Rank favors stocks that have recently seen positive revisions to their earnings estimates, so investors should rest assured that TGLS has an improving earnings 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 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.TGLS currently has a forward P/E ratio of 10.98, while FAST has a forward P/E of 30.15. We also note that TGLS has a PEG ratio of 0.55. This metric is used similarly to the famous P/E ratio, but the PEG ratio also takes into account the stock's expected earnings growth rate. FAST currently has a PEG ratio of 3.35.Another notable valuation metric for TGLS is its P/B ratio of 4.40. 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, FAST has a P/B of 10.21.Based on these metrics and many more, TGLS holds a Value grade of B, while FAST has a Value grade of D.TGLS sticks out from FAST in both our Zacks Rank and Style Scores models, so value investors will likely feel that TGLS is the better option right now. Infrastructure Stock Boom to Sweep America A massive push to rebuild the crumbling U.S. infrastructure will soon be underway. It’s bipartisan, urgent, and inevitable. Trillions will be spent. Fortunes will be made. The only question is “Will you get into the right stocks early when their growth potential is greatest?” Zacks has released a Special Report to help you do just that, and today it’s free. Discover 5 special companies that look to gain the most from construction and repair to roads, bridges, and buildings, plus cargo hauling and energy transformation on an almost unimaginable scale.Download FREE: How to Profit from Trillions on Spending for Infrastructure >>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 Tecnoglass Inc. (TGLS): Free Stock Analysis Report Fastenal Company (FAST): Free Stock Analysis Report To read this article on Zacks.com click here.