Ancient Gear Castle (SR03-EN023) - Structure Deck: Machine Reactor Unlimited

All "Ancient Gear" monsters gain 300 ATK. Each time a monster is Normal Summoned/Set, place 1 counter on this card. If you Tribute Summon an "Ancient Gear" monster face-up, you can Tribute this card instead, if the number of its counters is equal to or greater than the number of required Tribute(s).