What was the name of Google’s low-cost smartphone-based VR viewer introduced in 2014?

Google’s low-cost smartphone-based VR viewer introduced in 2014 was Google Cardboard.

Google Cardboard is a foldable virtual-reality viewer made mainly from cardboard, lenses, magnets or capacitive controls, and a user’s smartphone. Google presented the first version at its I/O developer conference in June 2014. The design let people experience stereoscopic VR without buying a dedicated headset.

Its importance came from accessibility rather than advanced hardware. Users inserted a compatible Android or iPhone into the viewer, and specially designed applications displayed separate images for the left and right eyes. The phone supplied the screen, processor, graphics, and motion sensors.

Google Cardboard is sometimes confused with Google Daydream, a later VR platform that included dedicated software and certified headsets. Cardboard was a simple viewer standard and ecosystem, not a single electronic headset model. Its inexpensive design helped introduce smartphone users and developers to basic VR concepts.