This skill is a must for anyone who wants to be able to custom modify their mecha, as it determines your character's ability to remove and integrate systems into your mecha. The higher the skill level, the lower the chance of a component being accidentally destroyed during installation or removal, and a high level also allows more complex equipment to be integrated into the mecha. Using this skill uses up some Mental Points.
This skill is trained, giving you improvements and experience points, by using it to install or remove components from mecha. So, for example, you can simply sit there installing and uninstalling that SF1 Mace into that spare Right Leg until eventually you fail badly enough to lose the Mace.