Gunjin

Gunjin: a human-type battle mech approximately seventy feet tall. There is a certain mathematical proportion between height, weight, and several other statistics regarding Gunjin mobile suit that designers and pilots call the ‘magic number’. The actual magic number is different for every design, but when it is reached the suit will have the best combination of speed, strength, operating window, and power output.

The material Gunjinite is named for the mech, not the other way around. Gunjins can be built entirely without the alloy, but it is the most easily mass-produced metal, the other being the much more difficult to manufacture (Gunzhanzhengjin).