Larry Page just received a bit of mail that he's probably not too happy about: a letter from members of US Congress who have a few concerns about Google Glass - and they want answers.

Eight members of the Congressional Bi-Partisan Privacy Caucus came together to create the letter, addressed to Page, which asks how Google is planning to protect people's privacy when the device goes mainstream.

They want to know whether Glass's facial recognition technology will reveal personal information about other people and whether Google will be storing data without user knowledge.

Explain yourselves

"We are curious whether this new technology could infringe on the privacy of the average American," it said.

"Please provide example of when Google would reject requests on Google Glass that would risk the privacy of others." The letter requests a reply no later than June 14.

Of course, the letter points to Google's recent big data debacle, which saw company fined over illegal Wi-Fi data capture, as another justification for its concern.

We've asked Google to comment on the matter, so we'll let you know if it does.