There's ultimately one major concern that haunts Apple (NASDAQ:AAPL) stock, dooming it to a paltry price-to-earnings ratio of just 13: uncertainty about the company's growth potential. When you're already the world's most valuable publicly traded company, moving the needle isn't easy. Fortunately, however, it's looking increasingly more likely that Apple will be launching an iWatch -- a product in a hot new category with potential to help Apple hack into new growth opportunities in the coming years.

What is the iWatch?
Probably the best way to imagine the potential of Apple's rumored iWatch is to look at the concept designs by Argentine design student Tomas Moyano. He imagines the new gadget as a lifestyle device with many different uses.

Iwatch Concept

iWatch concept design by Tomas Moyana. Images used with permission.

The grooves in Moyana's concept design allow for multiple looks with different bands, clips, necklaces, or anything accessory makers come up with to fit to the grooves.

Iwatch Concept

iWatch concept design by Tomas Moyana. Images used with permission.

While it's likely that Apple's actual iWatch will differ from Moyana's concept design, Moyana has done an excellent job of capturing the potential of a wearable device from Apple. Investors shouldn't think of the device as simply a watch that connects to their phone. Instead, it will likely be a lifestyle device with thousands of uses thanks to the iOS ecosystem and third-party developers.

Though details about the iWatch are still scant, rumors suggest the device will be available in both a 1.3-inch and 1.5-inch display, sport biometrics and other sensors, use iOS, and have four to five days of battery life. And in a surprising recent twist, the well-connect KGI securities Apple analyst Ming Chi Kuo says he thinks the high-end versions of the iWatch could cost more than $1,000.

The latest evidence
Yesterday MacRumors uncovered even more evidence that the iWatch is, indeed, among the new product categories Apple CEO Tim Cook has promised in 2014.

The company has been expanding its trademarks on "Apple" to also cover jewelry and watches in many regions.

MacRumors Editor in Chief Eric Slivka explains:

While some of Apple's trademarks on the "Apple" name have previously included some goods from Class 14 [a category that broadly includes jewelry, clocks, and watches], the company is now broadening and cleaning up its trademark applications in those areas.

Notably, however, Apple hasn't trademarked the company name under Class 14 in the U.S. yet.

Why investors should care about the iWatch
Though it's probably impossible to put a reasonable estimate to the potential of Apple's iWatch on Apple's business, it hasn't stopped analysts from throwing darts blindfolded. Ming Chi Kuo estimates Apple can sell about 5.5 million units this year and as many as 50 million next year. His scenario translates to about 10% plus revenue growth in the first year of iWatch sales. Morgan Stanley analyst Katy Huberty came up with a similar estimate of the impact of an iWatch on Apple's top line, although by different means.

At the very least, investors shouldn't ignore the fact that Apple is entering new categories. There are real implications for Apple's business -- and these implications are likely to be positive, given the company's proven track record of product launches. While analysts play the guessing game, Apple investors can at least take comfort in the fact that an iWatch at least will likely not only limit downside opportunity for Apple's business but also provide upside opportunity; these are the benefits of a conservatively valued stock with business catalysts in sight.

The best way to invest in the wearable tech revolution
The rumored iWatch will almost certainly have huge implications for investors. One hundred of Apple's top engineers are said to be busy building it in a secret lab. And Kuo's optimistic expectations for the device in 2014 and 2014 are just the beginning. An ABI Research report predicts 485 million iWatch-like wearable devices could be sold over the next decade. Fortunately there's a way for you to invest in this revolution today, for just a fraction of the price of Apple stock. Click here to get the full story in this eye-opening new report.

Daniel Sparks owns shares of Apple. The Motley Fool recommends and owns shares of Apple. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.