Once per turn, during your Main Phase, if you control this monster on the field, you can equip it to a face-up Machine-Type monster on your side of the field as an Equip Spell Card, OR unequip the Union equipment and Special Summon this card in face-up Attack Position. When equipped to a monster by this card's effect, that monster's ATK/DEF is increased by 500 points. (1 monster can only be equipped with 1 Union Monster at a time. If the monster that this card is equipped to is destroyed, this card is destroyed instead.)