Surface with attractive wood-look finish. Flexible height adjustment – stack units up to 4 sections high for different configurations and design possibilities. Each item is a set of 4 sections, these are the 4 edges that create one bed. Multiple sets can be purchased if you wish to stack them for higher beds. They work ergonomically at a comfortable height. They can also be used to set up an open composter space in your garden area. Compact, space-saving design. 5 years warranty.