Doc's spare parts are rewards from the Invention Tutorial, which gives 3 of them upon completion. They can be disassembled to obtain materials.
Analyse will state that it may yield blade parts, crafted parts, strong components, simple parts, smooth parts, and stunning components. However, Disassemble may yield precious components, flexible parts, base parts, deflecting parts, or living components as well.
Unlike the other Doc items, it can be banked.