Apple is set to release a mixed-reality headset called Reality, which will run on a new xrOS operating system and cost around $3,000. The device has been in development for seven years and has deviated from CEO Tim Cook's initial vision of a pair of unobtrusive eyeglasses that could be worn all day. Instead, the headset resembles a pair of ski goggles and requires a separate battery pack. The device is expected to be a major achievement for Cook and could be the foundation of a post-iPhone era for Apple. However, doubts remain about the device's potential success, given the lack of a real market for mixed-reality headsets.