What is the name of Google's low-cost VR viewer made of cardboard?

Google’s low-cost VR viewer was called Google Cardboard.

Introduced in 2014, Google Cardboard used a precisely cut cardboard enclosure, two lenses, and a smartphone to create a simple virtual-reality experience. Google published the viewer’s specifications and assembly instructions, allowing people to build one themselves or buy inexpensive versions from third-party manufacturers.

The phone supplied the display, processing, motion sensors, and VR apps; the cardboard viewer mainly held the phone at the correct distance from the lenses. This made Cardboard far cheaper and more accessible than dedicated headsets such as the Oculus Rift or HTC Vive. It supported both Android and iOS devices.

Google Cardboard was a platform as well as a physical viewer, so the name can refer to the headset design, the software ecosystem, or the overall VR project. Google later promoted the more advanced Daydream platform, while official Cardboard viewers were discontinued in 2021.