In January, the New York Police Department’s counterterrorism unit sent out a memo warning police officers about a new potential “security and counterintelligence” threat: Ray-Ban Meta glasses.

The memo directed officers to “conduct thorough inspections of all eyewear permitted within inmate cells” and cautioned that people who have been arrested could use these glasses, equipped with small cameras and microphones, to record inside police facilities. The memo cited two examples of such videos posted on social media.

“The ability to covertly record inside a law enforcement or detention facility, could result in a security risk if proprietary information about cell layouts, camera placements, or officer patrol/site protection routines are released,” the memo read.