Hardware needed for inserting in the device once it is 3d printed. - The number of bearings that are needed for the device are 13 units (8x22x7) - The DC motor used is a Hilitand 31ZY 24V/3.500RPM permanent magnet and there are 2 links where it can be found. This Bi-Generator VAWT have simple printable parts and it is very easy to assemble. In any case there is a bunch of 3d pics that helps visually step by step to assemble all the components of the device. There is a more detailed description link step by step available at instructables. If there is not much wind, the number of generators per unite can be reduced to one. It can be built an array of devices like this. https://www.kickstarter.com/projects/459381052/multi-stage-and-generator-wind-turbine-system