Image source: Oshkosh Corp.

What: Shares of equipment manufacturer Oshkosh Corp. (NYSE:OSK) jumped 15.5% in July after the company reported better-than-expected earnings results.

So what: Revenue for the fiscal third quarter was up 8.4% to $1.75 billion, but net income was down 6.1% to $84.2 million, or $1.13 per share. Defense as well as fire and emergency were the highlights, with revenue rising 36.1% for defense and 24.4% for fire and emergency, and both showing a sharp rise in operating income.  

For the full year, management now expects sales of $6.0 billion-$6.1 billion, up from previous guidance of $5.7 billion-$6.0 billion, and earnings per share of $2.60-$2.80, up from $2.30-$2.70 previously.

Now what: The quarterly results were impressive, but the guidance update is what should really catch investors' attention. It shows a longer-term improvement in the company's revenue and bottom line, and indicates that the pop in the defense and fire and emergency segments won't be short-lived. Shares aren't cheap at 20 times the top end of full-year earnings estimates, but if the performance continues, this could be a nice defense play for investors.