While all humans are about the same size, at least as far as the MUX is concerned, the Transformers (and certain aliens) come in all shapes and sizes. On the MUX we handle this by assigning each size category a number, and it effects the combat system in terms of ease-to-hit and damage done. It should be noted that size is actually a measure of volume, and to a lesser extent, weight. The chart lists the sizes in terms of length only for ease of comparrison. A gestalt is certainly not 180 feet tall, but it contains the volume and mass of at least 5 regular Transformers.