A virtual reality headset is a head-mounted device that provides virtual reality for the wearer. Virtual reality (VR) headsets are widely used with video games but they are also used in other applications, including simulators and trainers. They comprise a stereoscopic head-mounted display (providing separate images for each eye), stereo sound, and head-motion-tracking sensors, which may include devices such as gyroscopes, accelerometers, magnetometers or structured light systems. Some VR headsets also have eye-tracking sensors and gaming controllers. The VR glasses use a technology called head-tracking, which changes the field of vision as a person turns their head. The technology may not be perfect, as there is latency if the head moves too fast. Still, it does offer an immersive experience. The Sega VR, announced in 1991 and seen in early 1993 at the Winter CES, was never released for consoles, but was utilized for the Sega VR-1 motion simulator arcade attraction in 1994. Another early VR headset, the Forte VFX1, was announced at CES in 1994. The VFX-1 has stereoscopic displays, 3-axis head-tracking, and stereo headphones. Sony, another pioneer, released the Glasstron in 1997, which has an optional positional sensor, allowing the wearer to view the surroundings, with the perspective moving as the user's head moves, giving a deep sense of immersion.