Bujin Regalia - The Jewel

① Target 1 Rank 4 Xyz Monster you control; equip this card to that target.
② An Xyz monster equipped by this card gains 300 ATK for each of its Materials.
③ Once per turn, while this card is equipped to a monster by this effect:
You can attach 1 "Bujin" monster from your hand to the equipped monster as Material.