The main tube is of drawn polycarbonate, wound along its length with a semi-voxelated ferrule to resist collapse under heavy geometry, and terminates at the user end in a matched pair of frustum sleeves set at the inter-pupillary distance. The two lateral hand tubes are coupled to the main tube by means of a quaternion grommet, giving six degrees of freedom and a seventh, which we have been asked not to discuss.
Return flow, comprising head position, hand position and a small amount of embarrassment, is carried back up the tube in a counter-rotating annulus, separated from the incoming world by a sub-Lambertian gasket so that the two do not mix. Where they have been allowed to mix, the user has seen themselves from behind, which is covered under Fault 3.5 and not on this site.
Ambient sound is admitted at the side by way of a binaural louvre, and is turned through ninety degrees on entry so that it appears to come from the correct direction. Smell is not supported, and has been the subject of a standing request since 1992.