Google has announced that its wearable heads-up display, Project Glass, is now available for pre-order to Google I/O attendees for $1500 as an "Explorer Edition." Google showed off the technology once again at the June 27 I/O conference, but stressed it is not a consumer product.

At the I/O conference Google showed the device being used by skydivers and mountain bikers to record footage - which was live during the conference: the audience was asked if the wearers should jump, and it was done via a Google Hangout - and even switched between feeds (though this probably isn't possible if a pre-order is made). The package - a Project Glass device - was then handed to a person who jumped down the side of the building where the conference was taking place, before the bikers got the package and rode indoors.

Brin said the future of Project Glass is sharing moments live; the company previously showed photos of people riding bikes with the device, resting after a run, or unique moments such as a parent holding a child in mid-air.

Google also revealed during the conference that the prototype now weighs less than a pair of sunglasses, and uses a design that could work on prescription lenses or sunglasses. Video clips apparently run for three seconds, according to The Verge.

Google didn't show off the heads-up elements of the display, despite being the focus of an early video of the technology. Perhaps the technology isn't ready to be shown: some criticized the technology for causing the user's focus to switch between too many elements.

Sergey Brin, co-founder of Google, also allowed certain people to wear the device. One such person was Editor-in-Chief of The Verge, Joshua Topolsky.

The resolution isn't known, and the display was said to be small and only covered one eye. There's also sound, though it was barely audible. It can be worn over glasses: Brin said Google has been talking with sunglasses manufacturers and "standard eyglass" manufacturers to presumably get the technology to a wider audience.

Below is a behind-the-scenes video of the Project Glass demo.