Google has admitted that Nest Guard, the keypad and motion sensor device that’s part of the Nest Secure system, has a built-in microphone whose existence the company failed to disclose in any of the product’s literature.

The mic was outed because Google announced earlier this month that its home security system could also double as a Google Assistant smart speaker, with the company suggesting users could ask it if they need an umbrella on their way out.

Tuesday, a Google spokesperson told Business Insider that the company made a mistake in not previously disclosing that Nest Guard has a microphone, and that the mic is only turned on when users specifically enable that option.

“The on-device microphone was never intended to be a secret and should have been listed in the tech specs,” the spokesperson said. “That was an error on our part.”

Google’s admission comes as it and other tech companies struggle with myriad privacy-related controversies and calls to be more transparent.

Privacy and data-security concerns have sparked talk of regulation and California passed the Consumer Privacy Act last year.

The news also comes amid the rise of smart speakers such as Google Assistant, Amazon Echo and Apple HomePod, the voice-activated devices that carry out tasks such as playing music, reciting the news and setting alarms. Strategy Analytics reported this week that the devices were the hottest consumer electronics items in 2018, with more than 86 million units sold worldwide.

Memorable privacy lapses involving smart speakers include an Amazon Echo sending a recording of a couple’s conversation to someone on their contact list last year and when some of Google’s Home Mini speakers were found to be recording everything.