Fitbitblaze
FITBIT BLAZE. IMAGE SOURCE: FITBIT.

Fitbit (NYSE:FIT) faces no shortage of competitors, and that isn't likely to change in 2016. On the contrary, this year is shaping up to be the most competitive in the company's history.

Last month at the Consumer Electronics Show, firms unveiled dozens of new fitness trackers, all slated to make their debuts sometime this year. Some were smartwatches; others dedicated bands. All are poised to offer consumers greater fitness tracking capabilities, putting them in direct competition with Fitbit's products. Although Fitbit continues to lead the wearables industry, growing competition could eventually take a toll on the company's sales. Below are five gadgets Fitbit investors should keep an eye on this year.

Under Armour's HealthBox
Under Armour
(NYSE:UAA), in conjunction with Taiwanese handset giant HTC, unveiled an entire fitness tracking ecosystem at CES. The Under Armour HealthBox includes a fitness tracking band, chest strap, and scale. Consumers can purchase the entire box for $400, or they buy the components individually. The band and scale retail for $180 each; the heart rate monitoring chest strap goes for $80.

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UNDER ARMOUR HEALTHBOX. IMAGE SOURCE: UNDER ARMOUR.

Under Armour's business largely centers on its fitness apparel, but it's spent the last few years scooping up a variety of fitness-focused mobile apps (including, most notably, MyFitnessPal), which will work in concert with its fitness trackers. Under Armour's offerings are somewhat expensive, but its brand is stronger than Fitbit -- particularly among athletes -- and it has an extensive retail presence. 

Fossil's smarter watch
Traditional watchmaker Fossil (NASDAQ:FOSL) announced its second "smarter" watch at CES. Like last year's Q Grant, Fossil's Q54 Pilot looks like a traditional watch, but offers a number of smart features, including support for basic activity tracking and notifications. Last year, Fossil acquired Fitbit competitor Misfit in a deal that valued the company at $260 million. Management explained that it hoped to put Misfit's technology and app ecosystem to work, eventually outfitting all of its traditional watches with smart features.

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FOSSIL Q54 PILOT. IMAGE SOURCE: FOSSIL.

While Under Armour targets dedicated athletes, Fossil's smarter watches could appeal to the other end of the spectrum, stealing those Fitbit customers who are content with basic features.

The Misfit Ray makes fitness tracking fashionable
Despite its Fossil acquisition, Misfit continues to make devices under its own brand. At CES, it showcased the Misfit Ray, a fashion-focused tracker that offers basic movement and sleep tracking, notifications, water resistance, and a vibrating alarm. Similar to the Q54 Pilot, this device is likely to appeal to Fitbit's less engaged customers, but with its attractive design, could prove appealing.

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MISFIT RAY. IMAGE SOURCE: MISFIT.

Casio unveils a rugged Android Wear
Like Fossil, Casio is a longtime watchmaker. But when it comes to smartwatches, its strategy couldn't be any more different. Unveiled at CES, the Casio Smart Outdoor Watch is aggressively designed, bordering on garish. At $500, it's expensive, but it's powered by Android Wear, giving it access to a suite of third-party apps. Like other Android Wear devices, it offers basic fitness tracking capabilities, but sets itself apart with its rugged exterior that allows it to resist the elements. With a built-in compass, gyrometer, and accelerometer, the Smart Outdoor Watch appears aimed at outdoor enthusiasts.

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CASIO SMART OUTDOOR WATCH. IMAGE SOURCE: CASIO.

Garmin updates the Fenix3
GPS giant Garmin (NASDAQ:GRMN) showed an updated Fenix3 fitness watch at CES. Compared to its predecessor, the new Fenix3 offers a built-in optical heart rate sensor, allowing it to track the heart rate of its wearer without the need for a cumbersome chest strap. At $600, it's the most expensive device on this list, but it's by far the most compelling fitness tracker, with support for a wide variety of activities -- it can even be used in the pool.

Garmin's less expensive fitness tracking bands, sold under the Vivofit and Vivosmart brands, are viewed as more direct competitors to Fitbit's offerings. They're priced similarly and offer similar features. But as Fitbit moves upmarket (its new Fitbit Blaze retails for $200), it will come closer to competing more directly with Garmin's high-end fitness watches.

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GARMIN FENIX3 HR. IMAGE SOURCE: GARMIN.

On top, but for how long?
Fitbit sold more wearable devices than any other company in the third quarter last year, according to research firm IDC. It sold 4.7 million trackers, capturing just over 22% of the market. It sold more than four times as many trackers as Garmin, while Fossil, Misfit, HTC, Casio, and Under Armour didn't make the top five.

Still, the market for wearables remains in its infancy. With increasing awareness and a strong app ecosystem, Fitbit could maintain its lead. But rising competition will make that prospect increasingly difficult, in 2016 and beyond.

Sam Mattera has no position in any stocks mentioned. The Motley Fool owns shares of and recommends Under Armour. The Motley Fool recommends Fossil. Try any of our Foolish newsletter services free for 30 days. We Fools may not 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.