When the wearer fights a challenge he can 'swap' his base Weapon Skill, Strength, Toughness, Initiative and Attacks values with those of his enemy. He can choose not to use the mirror, but if he does he must swap all these characteristics for the duration of the challenge. So, the wearer fights with his enemy's WS, S, T, I and A whilst his enemy fights with the wearer's WS, S, T, I and A.