The Big Buttresses Pack is part of the Castle Builder System. It is made of "Dwarvenite". This item was initially available as an add-on to a pledge level during the Castle Builder System Kickstarter. It was not advertised during the Kickstarter campaign but was made available during the final order. The item comes in both painted and unpainted versions.
The Big Buttresses Pack comes with these 12 pieces:
(4) Perched Gargoyle
(4) Flying Buttress