Our grey Boulder Pack features 15 different large boulders. They all come in various grey shades with highlighting. They can be used individualy or placed and stacked together to form larger boulder formations, ridges, caves, recesses, archways and tunnels. These boulders can be used in conjunction with our Hoodoo Packs and other Rock and Boulder Packs. All of our rocks and hoodoos are made from lightweight natural materials.