The Arduino MKR family is designed for manufacturers and engineers to quickly develop IoT projects. What sets the MKR boards apart from other Arduino boards is the 67.64 × 25 mm MKR form factor, computing power and features.
With one exception, the MKR boards are equipped with on-board connectivity modules ranging from Wi-Fi to GSM. Other boards support Narrowband IoT, Lo-Ra and SigFox networks (in Europe), while shields can be added to create Ethernet and CAN (Controller Area Network) connected projects.
If you need wireless connectivity for your development that works on a specific connectivity platform (Wi-Fi, Lo-Ra, GSM or SigFox) and want to start developing quickly, the MKR series is a very good choice, especially with the ability to use most Arduino shields with the MKR2UNO board.