Basically, smartwatches are wearable-technology devices that maintain a relatively persistent wireless connection to your mobile device—usually a smart phone—and can receive notifications of incoming calls, texts, instant messages, social-network updates, and more, from that device. Some can also let you accept and conduct phone calls right on the watch. And even newer models (the Samsung Gear S, for one) can act as smart phones all on their own, without needing a paired phone nearby.
In June 2000, IBM displayed a prototype for a wristwatch that ran Linux. The original version had only 6 hours of battery life, which was later extended to 12. It featured 8 MB of memory and ran Linux 2.2. The device was later upgraded with an accelerometer, vibrating mechanism, and fingerprint sensor. IBM began to collaborate with Citizen Watch Co. to create the "WatchPad". The WatchPad 1.5 features a 320 × 240 QVGA monochrome touch sensitive display and runs Linux 2.4. It also features calendar software, Bluetooth, 8 MB of RAM and 16 MB of flash memory. Citizen was hoping to market the watch to students and businessmen, with a retail price of around $399. Epson Seiko introduced their Chrono-bit wristwatch in September 2000. The Chrono-bit watches feature a rotating bezel for data input, synchronize PIM data via a serial cable, and can load custom watch faces.
The top smartwatches that debuted at the 2017 Consumer Electronics Show included the Casio WSD-F20, Misfit Wearables Vapor and the Garmin Fenix 5 series. Apple released on September 22, 2017 their Apple Watch Series 3 model which offers built in LTE cellular connectivity allowing phone calls, messaging and data without relying on a nearby smartphone connection. 
While testing the Q Venture, we found the response time to be pretty solid when it came to calls and notifications. The typical response time for a notification was somewhere around 10 seconds. We were, however, able to immediately ignore calls. This quick response time should give you plenty of time to retrieve your phone from your pocket or fish it out of your purse.
Our top pick for most people is the Apple Watch Series 4 with GPS (starting at $399), which has a huge display, ultra-fast processor, Raise to Speak Siri, fall detection and a built-in electrical heart rate sensor for taking on-the-go electrocardiograms. It also runs watchOS 5, which makes the watch even more useful with automatic workout-tracking, offline podcast playback and a Walkie-Talkie voice chat feature.