Use these molds to cast the rocks to line the edges a creek river etc. Molds are flexible and reusable. Rocks range in size from smallest: 1 3/8 L x 3/8 W x 3/32 H to largest: 3 7/8 L x 1 W x 3/32 H NOTE: All Creek Bank rocks are 3/32 high. The ends of each rock are 3/16 wide so they can be installed flush for a seamless transition from one rock to another. About Rock Molds Ready Rocks™ Custom & Debris Model any rock from anywhere. Cast or carve your own; install ready-to-go hand-painted rock; and pile debris under rock faces and along road cuts.