Advanced format ruling
Armor Breaker
Card effect (current official text)Once per turn, you can equip this card to a Warrior-Type monster you control, OR unequip it to Special Summon this card in face-up Attack Position. While equipped to a monster by this effect, when that monster inflicts Battle Damage to your opponent, destroy 1 card on the field. (A monster can only be equipped with 1 Union Monster at a time. If the equipped monster would be destroyed by battle, this card is destroyed instead.)
Current rulings for this card are maintained by Konami.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Advanced forum — sourced change requests get reviewed.