At a time when there is so much volatility happening overseas, Jim Cramer says investors need to pay attention to foreign currency exchange rates versus the U.S. dollar.

After all, a strong dollar has the ability to wreak major havoc on all U.S.-based international companies because when they translate sales from weak currencies overseas, that could mean fewer dollars.

"If you're not paying attention, these currency issues can come out of nowhere and body slam your portfolio," the "Mad Money" host said. (Tweet This)

In addition, Cramer thinks that Thursday's Federal Reserve decision of whether to hike interest rates could have major impact on currencies around the globe. To get a better sense on where the currency markets could be headed, Cramer spoke with Bob Lang, a technician, founder and senior strategist at ExplosiveOptions.net as well as Cramer's colleague at RealMoney.com.

"Whether or not we get a rate hike is a gigantic deal for 2015, and it will certainly matter to the trajectory of the dollar, not to mention a host of foreign currencies, especially the ones from smaller emerging market countries," Cramer said.

Lang's position is that if the Fed does tighten, it will do it in a responsible way and try not to spook the markets. However, when Lang turned to the charts to get a read on where investors think the Fed's decision could be headed, he was surprised to find that investors don't seem to be preparing for any kind of Fed-induced dislocation.

First, Lang took a look at the CBOE Volatility Index, or VIX, which measures the level of implied volatility in put and call options on the . It is often widely used to determine the level of fear in the stock market. Lang found that the VIX has dropped sharply in the past few weeks, which indicates that investor fear has gone down as the Fed meeting approaches.

He then analyzed the Fed Fund futures, which are futures contracts designed to let traders bet directly on where the Federal Reserve will take short-term interest rates. Based on the difference between September and October Fed Fund futures, Lang calculated that the futures market is signaling only a 13 percent probability of a rate hike this week.

Lang also found telling action in the CBOE SKEW option index, which measures the tail risk of the S&P 500. This refers to the probability that the averages will get hit by a huge and unforeseen selloff. It tends to rally dramatically when investors are worried that things could go downhill. However, Lang found that since Labor Day this index has basically fallen off a cliff.

All of this data led Lang to determine that regardless of what happens investors are not worried about a selloff after the Fed meeting.

And if the Fed really is on hold, Lang said he could make a bullish case for the euro, which is great news for U.S. industrials, drug companies and consumer packaged goods firms. He also looked at the weekly chart of the FXE, the ETF that measures the strength of the euro versus the dollar.

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At its current levels, the FXE is only a few points away from its 50-week moving average. If it can break out above $113, Lang thinks it could go all the way to $120, which could represent a huge rally in the euro and prompt investors to buy stocks of U.S. based international companies.

Ultimately, Lang thinks that investors should not sweat the upcoming Fed meeting. And if the Fed does not raise rates, this could cause the euro, and even the yen, to roar.

"I think this is a huge call and, again, I remind you that if the dollar gets weaker then 2016 earnings estimates for all but the pure domestic companies will be going higher, which is something that could knock this bearish phase for so many international stocks right off its tracks," Cramer said. (Tweet This)

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