Smartwatches are wearables that you wear on your wrist like a regular wristwatch. These are much cheaper than smart glasses and, as a result, more common for the average person to own. Instead of being "in your face" like smart glasses, smartwatches may do things such as alert the wearer to text messages or posts on social media, display weather alerts, keep track of events, and of course, display the time. Additionally, some smartwatches have similar capabilities to healthwear and keep track of heart rate and steps taken. Smartwatches often act as an extra interface for devices such as smartphones and can control music or answer phone calls. One of the most well known smart watches is the Pebble smartwatch by Pebble, although some more well known brands such as Samsung and Apple have moved into the smartwatch market with the Gear and the Apple Watches. Other smartwatches include the Tok, the U watch, and the Sony SW series. Most smart watches cannot operate standalone although more and more are being developed to break free from this requirement. Smartwatch screens vary in size and shape which means that developers need to be versatile when developing apps for smartwatches. Fortunately, operating systems such as Android Wear often include the basic tools needed for developers to develope one app that works on many devices without changing too much of the code.