This VR doesn't need any other component (maybe few drops of glue only). The parts 6,
7, 8 and 9 (straps and foam) should be printed with a flexible material. However, regular straps and foam strips can be bought and attached to the headset instead of the proposed designs. This VR headset is fully adjustable, but if you still have a small issue with the focus try to switch places on the parts 2a and 2b.The size of the lenses is at 37mm.
B' Update: Two types of straps with length at 190mm and 250mm. Also, an extension was added.
A' Update: The length of the smartphone holder has been increased at 140mm approximately.
Components and print list on: http://horizonlab.co/2017/05/28/vr-headset-fully-3d-printed