The first retail edition of PlayStation VR will require an external processing unit that has been estimated to be roughly the same size as Nintendo's Wii console.

PlayStation VR units will use the external processor to ease the burden of rendering virtual reality graphics. The headset will plug directly into the unit, which in turn is connected to the PS4.

According to a Polygon report, pictures of the device were not permitted when demonstrated at a recent games event, but from memory the reporter claims the device is "a bit smaller than a Wii".

Nintendo's Wii measures about 4.5cm wide, 16cm tall, and 22cm deep. By volume, the PlayStation 4 is roughly three times bigger.

PlayStation VR, previously codenamed Morpheus, represents the corporation's big gamble in the revived virtual reality market. Despite its development stretch now entering its third year, a final price and release date has yet to be set.

This is true too of Sony's rivals in virtual reality, such as Oculus VR (bought by Facebook) and Vive VR (delayed to 2016). It appears none of the three key competitors are ready to set a price point for the luxury peripheral, with costs considered a key obstruction to mass-market adoption.