China’s police have been testing sunglasses with built-in facial recognition since at least last month to catch suspects and those traveling under false identities. Now China is expanding the facial recognition sunglasses program as police are beginning to use them in the outskirts of Beijing, according to Reuters. The program was used as extra security while Parliament voted to extend Xi Jinping’s presidency to a lifetime rule, and paralleled the increased censorship and surveillance measures seen throughout China.

Police used the sunglasses to check travelers and car registration plates against the government’s blacklist before Parliament’s annual meeting this past weekend. The Chinese government has a list of people who are not allowed to enter the meeting and might face additional enforcement action. The blacklist includes criminals, journalists, political dissidents, and human rights activists, among others.

Previously, the glasses were only been tested in trains stations in Zhengzhou, the capital of Henan Province. By February 8th, police had allegedly caught seven suspects, and 26 travelers using false identities.

The sunglasses are controlled by a mobile unit and cost $636 (3,999 RMB), with an additional cost for facial recognition support. They give police “instant and accurate feedback” compared to the lag and static of using facial recognition through CCTVs as Beijing-based LLVision Technology’s CEO Wu Fei told the Wall Street Journal last month.