Google says one of its least expensive innovations - virtual reality headgear made of cardboard - has become a huge hit.
The tech giant says it has a new version of its cardboard gadget, which consumers can buy for as little as $5.20.
The playfully named Google Cardboard debuted last year at the internet giant's annual developers' conference.
One simply folds the cardboard into goggles of a sort that have eyeholes opening into a slot designed to hold smartphones that serve as display screens for immersive videos.
"It took off; people keep finding new and creative uses of Google Cardboard virtual reality," vice-president of product management Clay Bavor said at a Google I/O developers gathering. "One guy even proposed to his girlfriend using Google Cardboard. I'm not sure how that worked, but I hope she said yes."
