Google Glass invites have been sent out in the US, encouraging more users to wear the smart glasses with a built-in camera.
Early adopters of the Glass Explorer program have received the following email from Google, reports Mashable: "We love demoing Glass to our friends. We've perfected our 'OK Glass, take a picture' faces so that the shot captures us smiling, laughing and looking chic. Well, maybe not all at the same time.
"Mostly, we love sharing Glass with our friends, because adventures through Glass are more fun with others. Here's your chance to invite one friend into the Glass Explorer Program. Complete this form and share Glass with a friend, funny demo face and all."
The invites are currently limited to friends of people who already own Glass, and US residents at least 18 years old who can pick up a device in New York, Los Angeles or San Francisco.
Google has confirmed the new invites for Google Glass, and says these have been sent out to a "small" number of users.