Achieve the look of real stone without the intense labor! The stones in this kit are made of polyethylene, a UV-resistant material, which ensures that these stones will retain their realistic look even in the hot sun. And although they are lighter than real stone, these raised beds are strong enough to sit on. All 10" High CurveRock Raised Bed Kits come with four 18" steel spikes secure the system and anchor it to the ground. Four sections that create the 4-foot diameter, as shown in the photograph. The interior diameter is 3 feet, and each curved section is 10" high x 6" deep. Please allow 1-2 weeks for delivery.