With 'VR Video Play' you play your own videos next to each other. This is suitable for e.g. Cardboards, so VR glasses where you insert the smartphone. You open a video and it is played twice synchronously. For the left and right eye. Eyeglasses without screen (Samsung Gear VR, Google Cardboard or Zeiss VR One and others). Here you put the smartphone into the glasses and use its screen. It is the cheapest with the Goggle Cardboard as a version of cardboard for approx. 8 USD.