In 2013, X acquired Makani Power, a US company which develops tethered wings/kites with mounted wind turbines for low cost renewable energy generation.[60] In 2014, it acquired product design and mechanical engineering firm Gecko Design, whose previous products included the Fitbit activity tracker and low-cost computers.[61] As of 2015, X has acquired 14 companies: among them are Redwood Robotics, Meka Robotics, Boston Dynamics, Bot & Dolly, and Jetpac.[61] In June 2017, X sold Boston Dynamics to SoftBank Group,[62] which later sold it to Hyundai Motor Company in December 2020.