LifeRock Donuts are the perfect statement piece for any saltwater aquarium! Hand-crafted from real aragonitic base rock, they feature extensive macro and micro-porosity to provide outstanding biological performance, while remaining safe for all fish and inverts. Each piece is totally unique, making it an environmentally responsible choice. With a diameter of 8 inches and a depth of 2-3 inches, the donuts look natural and beautiful - perfect for creating instant swim-through spaces and coral seats. And with 4 pieces per box, you can easily create a stunning aquascape! Note: Rock is fragile and not insurable.