This is your skill at assembling and repairing computer hardware. You know how everything fits together and what works best and what doesn't. At lower levels, this is just for personal devices. At the higher levels, you understand super computers, servers, and custom machinery. When combined with Electric Systems and a good lab, you can make improvements to micro-processors and other delicate technologies. Designs based on Quantum computers would require an amazing array of Science skills to back you up.