"One of the biggest joys in the stock market is finding a small fish that will become a big one," Jim Cramer said on his "RealMoney" radio show Wednesday. One of these small fish, he said, is Dynamic Materials ( BOOM). This is a small-cap company that is engaged in the manufacture of metal cladding, which toughens weak metal, he said. "A lot of people felt that BOOM was a cyclical stock," he said. However, he said while looking at the refinery business, he sees that there are not enough refineries around, and as people start building more refineries, they are going to need BOOM. Although there are only two analysts covering this stock, and a lot of people are betting against it, Cramer believes it is a long-term positive story. "It is one of those stocks that you can buy and put away," he said. "I like the company and I like its business." The financial world is filled with indices, Cramer said. There is the Dow, which follows the 30 largest public companies, the Nasdaq, which follows tech stocks and then there are exchange-traded funds or ETFs, which follow the energy and aerospace sectors. On Wednesday, Claymore Group announced it is launching an ETF with little or no coverage, and it is also trying to launch an ETF with insider buying. Cramer said this is ridiculous and is indexing for the sake of indexing. All these ETFs do is confuse people he said, adding that the best reason to be in a mutual fund is to cushion you against a decline and diversify yourself. With that he suggested going into Vanguard's mutual funds, which have the lowest cost fees and are very good at buying stock, he said. To see the most recent edition of The RealMoney Radio Recap in its entirety, please click here. This recap is published every day around 3 p.m. ET.