When this card on the field is destroyed and sent to the Graveyard, you can add 1 Union monster from your Deck to your hand. Once per turn, during your Main Phase, you can equip this card to a Machine-Type monster you control as an Equip Card, OR unequip it to Special Summon this card in face-up Attack Position. (A monster can only be equipped with 1 Union Monster at a time. If the equipped monster would be destroyed, destroy this card instead.)