Online gadget retailer I Want One of Those is selling a screen protector for iPhone that can also be used to view glasses-free stereoscopic 3D. No, really.

The EyeFly 3D screen protector sticks to the front of an iPhone 4S, 5, 5S, 5C or fifth generation iPod touch and displays 3D videos and images from sites such as YouTube. It uses micro lens technology with over half a million lenses presenting different perspectives of the same image to each eye.

The manufacturer also claims that there is little pixelation, so the phone's screen brightness and clarity is not affected in normal 2D use. And as the EyeFly 3D is made from 9H tempered glass, it also helps protect the iPhone screen.

EyeFly has its own video player and photo editing apps, which are required to view and manipulate 3D content. They are free to download from the iTunes App Store and can be used to watch any stereoscopic videos on YouTube. Users can also import content into the app from the internet or 3D cameras.

There is also a 2D to 3D conversion mode for still images.

IWOOT is selling the EyeFly 3D for £14.99 and it's available now. The protector will only work on the phones it is designed for, but is easy to install.