the virtual reality headset is available to buy from firebox for £ 29.95 .
it works with android and ios phones via virtual reality apps and 3d films .
the maximum size of the device must be 3.5 x 5.7-inches -lrb- 8.2 x 15.4 cm -rrb- .
it calls itself an affordable alternative to rivals such as oculus rift .