Popular Smart Watches in the market.

 Smart Watches

There are already dozens of smart watches for sale. Here are a few of the most–talked-about versions.

The Sony SmartWatch 2 features a 1.6-inch (4-centimeter) square touchscreen face in a body that's 0.3 inches (7.6 millimeters) thick. The touchscreen recognizes typical gestural commands, including swipe and pinch, and you can display a digital or analog-ish clock face by default. It's water resistant and has NFC capabilities, in addition to Bluetooth. In a nod to the importance of looks, Sony lets you substitute any 24-millimeter (0.94-inch) watchband for the rubberized factory model. It comes with a USB port for data transfer and charging, and under moderate use, the battery lasts about four days.

The SW2 is designed to pair with a number of Sony smartphones through Bluetooth. Once paired, you'll be able to use the watch to reject or mute phone calls, receive a call (if you have a compatible headset), control music playback, and check Facebook, Twitter and text messages. Because SmartWatch 2 is an Android device, you can download many apps from the Google Play store and run them on your watch. Sony indicates that there are around 200 apps specifically designed for SmartWatch. As of late 2013, it retailed for about $200.

A startup company called Pebble makes one of the best-selling smart watches as of late 2013. The $150 Pebble watch actually backs away from attempting to duplicate your smartphone's functions. Instead, it does a few things very well, and in a package that's more stylish than most other models. For example, you can choose from hundreds of watch faces to change the look of the watch with just a press. Pebble is 2 inches (5 centimeters) long, 1.4 inches (3.6 centimeters) wide and 0.4 inches (10.2 millimeters) thick.

It features an ARM Cortex-M3 processor and a 3D accelerometer, which is helpful when using the watch in tandem with an athletics-minded app like RunKeeper on your phone. It's also waterproof and boasts weeklong battery life. Instead of using a power-sucking touchscreen LCD display, it has a monochrome e-paper screen like the ones you see on digital book readers. That means you'll have to navigate menus using side-mounted buttons.

Pebble works with both Android and iPhone operating systems. Once paired to your smartphone through Bluetooth 4.0, the Pebble displays message text and allows you to control music playback. The maker promises that many more features are forthcoming.

Samsung's $300 Galaxy Gear is loaded with features, including 4GB memory, voice command input, a 1.9 megapixel camera (for both video and stills), voice memo, pedometer and speaker. It has a 1.6-inch (4.1-centimeter) display, and is nearly half and inch (about 1.3 centimeters) thick. It's designed to work seamlessly with apps such as Runtastic and RunKeeper. Samsung also includes a version of Evernote that's been tweaked to work best with their watch, so that you can easily pair photos and voice notes in a rush.

Goophone, a company perhaps best known for selling counterfeit iPhones, is taking the smart watches seriously. The Goophone Smart Watch is a wholly independent device; that is, it actually has built-in antennas so that you can use it to make calls sans your smartphone. A 2G version costs $250, while the higher-speed 3G variant is $300. It's equipped with a 1.5-inch (3.8-centimeter) screen, a 1.2GHz processor, 512MB of RAM and a 2-megapixel camera. It is truly a smartphone crammed into a wrist-mounted body. It runs on an older version of the Android operating system, which means that it won't work with many newer apps.