Precast plaster and hand-painted. Each rock is unique. Use Creek Bed rocks to model dry creek beds or to set prior to pouring Realistic Water(TM), sold separately, for creeks, rivers and streams and other waterways. 31 rocks. 1-3/8 to 4′ Ready Rocks Shelf Rocks Faceted Rocks Rock Faces Rock Outcroppings Surface Rocks Creek Bed Rocks Boulders