Shareholders in Polaris Industries ( PII) are having a stellar year in 2013; shares of the $9 billion ATV manufacturer are up more than 55% since the calendar flipped over to January. But even if you missed the move, you shouldn't ignore this stock. PII looks like it's still got higher ground ahead of it. >>4 Stocks Spiking on Unusual Volume That's because Polaris is currently forming an ascending triangle pattern, a bullish price setup that's formed by a horizontal resistance level above shares at $137 and uptrending support to the downside. Basically, as PII bounces in between those two technical levels, it's getting squeezed closer and closer to a breakout above $137. When that happens, we've got a buy signal in shares. Relative strength has been in an uptrend since the start of the summer, a fact that adds some extra confirmation to the trade. Polaris has been outperforming a serious bull market. If you decide to take the $137 breakout, I'd recommend keeping a protective stop on the other side of the 50-day moving average.