Dynamo Rocks! promote movement, balance and exercise. Made of UV-stabilized fiberglass, molded from actual rocks for a realistic appearance. In addition, sand-filled gel coat provides a texture that resembles actual granite. Select from three sizes of rocks. Small boulders accept five children, ages 2 to 5; measure about 7.5 ft. long, 5 ft. wide and 3.5 ft. high; and weigh 620 lbs. Medium rocks accept eight youngsters (5 to 12 years old); measure approximately 12.5 ft. long, 8.5 ft. wide and 6 ft. high; and weigh 1,200 lbs. Large boulders accept 12 children (5 to 12 years old); measure 12 ft. long, 6 ft. wide and 8 ft. high; and weigh 1,700 lbs. All rocks contain an anti-graffiti coating. Optional flame-resistant material is available. Dynamo Playgrounds, Ottawa, Ontario