What: Shares of specialty vehicle maker Oshkosh Corporation (NYSE:OSK) fell as much as 12% today after it reported fiscal fourth-quarter results.

So what: Net sales fell 5.4% in the quarter to $1.58 billion and net income dropped 35% to $50.3 million, or $0.64 per share. Adjusted for one-time items, earnings were $0.67 per share, but that still fell short of analysts' expectation of $0.78 per share. 

What really worried investors was management's expectation for $3.00 to $3.40 per share in earnings during fiscal 2016, which was lower than their previous estimates and below Wall Street's current estimate of $3.53 per share.

Now what: Management's comments about commercial and military activity were actually pretty positive and indicated an uptick in demand is coming. But guidance was lowered due to a "more cautious outlook" for the business and uncertainty around when the uptick in demand will take place. With shares trading at just 11 times the top end of guidance, I think this is a great buying opportunity for long-term investors. There's uncertainty ahead, but the macro demand environment for Oshkosh's products looks to be at a bottom, and next year we should see improvement throughout the year.