CNT210 (OTTO) Multi-walled carbon nanotubes, 95% (OD: 20-30 nm, ID: 5-10 nm, Length: 10-30 um) - used to make bullet- proof jackets. Carbon nanotubes can be used to make aircraft and spacecraft bodies. Carbon nanotubes can be used to build high-performance nanoscaled thin-film transistors to replace silicon-based transistors because of the semiconducting properties of carbon nanotubes.