Context & problematicDigital technology is getting a more and more important place nowadays. A few decades ago, having an instantaneous discussion with someone at the other end of the word was unreal for some people. Even less thinking about having a computer in our pockets. Now, it’s even possible to have wearables devices. Even if the Internet of things is getting more and more present in the everyday life, it is still uncommon. In 2015, around 50 millions of these products have been sold in the world, being a market of 2 billion dollars. This means that technology, and wearable technology in particular are taking an important place in the high-tech domain since a few years. Why wearable technology are going to become essential ?In this document, I am going to analyze the wearable devices universe and their uses. Next, I am going to do the inventory of the actual market and its evolution. And then, I will study the limits, the risks and the advantages of these new devices.What is a wearable device ?This term refers to an electronic object that can be worn, such as a clothe or an accessory. Many wearable devices exist. The fact that they are connected to Internet, straight from a smartphone or a computer is one of the most important characteristic of these products. We can send and receive informations thanks to the wearable device. Here is a descriptive of the most popular products today.The most popular wearable devices are the smartwatch and the sportwatch. First, they permit to track the physical activity during the day, and to know the sleep quality of its user. During a sport session, it is possible to know how much you ran, your heart rate, to record your process, and to see it on a map. On top of that, it is possible to read texts from our smartphone on the watch screen. Also, some models allows to make phone calls.Wristbands do quite the same thing, but since there’s no screen, that can read texts. There are also other types of wearable devices, such as the Bluetooth headsets, that allow to listen to music from a smartphone (or other tools that can generate sounds) without any wires linking them.Another wearable devices that become that become more and more important on the market are the Head-mounted display. Some of these headphones permit to see virtual reality, others allow to see augmented reality. The only difference between these two kind of headphones is that one releases a virtual image, and the other one releases an image that adapts itself to the environment around the user. The Google glasses are in the category of augmented reality. Indeed, there is a part of them that releases an image.Also, another type of wearable devices exists. The eyewears that are connected glasses, allowing the taking of photographs. It also allows to send them on our favorite social networks.Current market and forecastsToday, the wearable devices market is divided in four major devices : the smartwatches, the wristbands, the head-mounted display and the bluetooth headphones. The smartwatch market is dominated by Apple and Samsung. This market is getting mixed up with the wristbands market, because of the quite similar functionalities of these two products. Fitbit and Xiaomi dominate this market. The bluetooth headphones market is dominated by Beats and Bose, and the head-mounted display by Oculus VR and Microsoft Hololens.In 2017, 310.4 million of wearable devices have been sold in the world, which represents a 30.5 billion dollars market. It is divided in 41.50 million of units sold this same year, 21.43 of sport watches, 150 millions of units for bluetooth headsets, 22.01 of head-mounted display and 44.10 of wristbands.In 2021, Gartner predicts an increase in every category, that is to say a rise of 95% of sold units, 4% of sport watches, 37% of units for bluetooth headsets, 205% for head-mounted display and 44% for the wristbands.