While internal hardware varies, most have an electronic visual display, either backlit LCD or OLED or Hologram.[4] Some use transflective or electronic paper, to consume less power. Most have a rechargeable battery. Peripheral devices may include digital cameras, thermometers, accelerometers, pedometers, heart rate monitors, altimeters, barometers, compasses, GPS receivers, tiny speakers, and SD cards, which are recognized as storage devices by many other kinds of computers.
You can also use devices that support the Google Wear operating system in conjunction with an iPhone as well as a Samsung Gear device that runs Samsung’s own Tizen operating system. But Google Wear and Tizen devices are designed to pair with smartphones using the Android OS, so you won’t get full functionality when pairing with an iPhone. For instance, some Android smartwatches carry Samsung’s smartwatch line-up and naturally enough, work best with Samsung smartphones, but are still compatible with Android-powered Huawei or Nokia phones.
The Galaxy Watch comes in two sizes, 46mm and 42mm, both with an OLED display and an “optimized” chipset that extends battery life. For the larger model, you can squeeze 6 days out of a single charge while the smaller model still offers up to 4 days. As you’d expect, the Watch also includes features like GPS, water resistance, and there’s NFC for Samsung Pay.
I've been pleased to see swim-tracking trickle down into more affordable devices over the past few years. Fitbit's Flex 2 remains its most affordable device with swim-tracking features, priced at $60. But the $150 Charge 3, with its big display and smattering of smartwatch capabilities, is for a different audience than those who would gravitate to the tiny, quasi-cylindrical Flex 2. Even if you don't swim often, water-resistance up to 50 meters means users don't have to worry about showering with the Charge 3 or dropping it in the pool by accident.
Smartwatches are still a relatively new electronics category, but these devices are poised to hit the mainstream. This year we saw major players such as LG and Motorola throw their smartwatches in the ring, along with Samsung, Sony, and a host of smaller companies like Pebble and Martian. And Apple finally confirmed its entry, the innovative Apple Watch, expected to arrive early in 2015.

Google confirmed to Tom's Guide that the company won't be releasing its own Wear OS smartwatch this year. The news comes after months of rumors that a Google-branded Pixel Watch running on Qualcomm's latest processor would be launched at Google's October hardware event. Instead, Google plans to focus on adding features to Wear OS on the software side and support the companies who are currently making Android smartwatches. Google's hardware event is Oct. 9.
×