Iron copies

Meaning
The word Iron copy can mean the following:


 * Suit(s) that has(have) the same statistics as other suit.
 * Suit(s) that don't change the model.

Why does this exist?
A lot of the suits use the same statistics as the Mark 2. Instead of calling them "Mark 2 but only changes the model of the suit and doesn't even get different stats" they are called Iron copies.