Investors interested in Medical - Instruments stocks are likely familiar with Integer (ITGR) and Abiomed (ABMD). But which of these two stocks presents investors with the better value opportunity right now? 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 proven Zacks Rank emphasizes companies with positive estimate revision trends, and our Style Scores highlight stocks with specific traits.Right now, both Integer and Abiomed are sporting a Zacks Rank of # 2 (Buy). This system places an emphasis on companies that have seen positive earnings estimate revisions, so investors should feel comfortable knowing that these stocks have improving earnings outlooks. But this is just one piece of the puzzle for value investors.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.The Value category of the Style Scores system identifies undervalued companies by looking at a number of key metrics. These include the long-favored P/E ratio, P/S ratio, earnings yield, cash flow per share, and a variety of other fundamentals that help us determine a company's fair value.ITGR currently has a forward P/E ratio of 20.40, while ABMD has a forward P/E of 118.54. We also note that ITGR has a PEG ratio of 1.36. 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. ABMD currently has a PEG ratio of 4.39.Another notable valuation metric for ITGR is its P/B ratio of 2.38. 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, ABMD has a P/B of 26.62.Based on these metrics and many more, ITGR holds a Value grade of A, while ABMD has a Value grade of D.Both ITGR and ABMD are impressive stocks with solid earnings outlooks, but based on these valuation figures, we feel that ITGR is the superior value 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 Integer Holdings Corporation (ITGR): Free Stock Analysis Report ABIOMED, Inc. (ABMD): Free Stock Analysis Report To read this article on Zacks.com click here.