An exhibitor shows riot gear for police during the China International Exhibition on Police Equipment in Beijing, capital of China, May 15, 2018. Over 500 exhibitors from home and abroad took part in the exhibition from May 15 to 18. (Xinhua/Yin Gang)

Zhang Changqing, an exhibitor of the Ministry of Public Security of China, introduces a genetic analyzer during the China International Exhibition on Police Equipment in Beijing, capital of China, May 15, 2018. Over 500 exhibitors from home and abroad took part in the exhibition from May 15 to 18. (Xinhua/Yin Gang)