A visitor drives a Ninebot Gokart at the booth of Segway-Ninebot during the 2019 IFA fair in Berlin, capital of Germany, on Sept. 6, 2019. The 59th Consumer Electronics Unlimited (IFA) fair, Europe's biggest consumer electronics show, opened in Berlin on Friday, with the latest products and innovations from the leading global brands. (Xinhua/Shan Yuqi)