The "Novistone" stacked polymer stones panel is usually used for retaining walls. The panel covers approximately 50 square foot. Onyx stones harmonize with all siding types. They are resistant to expansion, contraction, cracks as well as discoloration caused by ultraviolet rays. They also resist wind and impacts. Being maintenance free, it is a lightweight, easy and quick to install material. The panel measure 45 3/8'' x 20 1/2" and comes in a box of ten units a coverage area of 50 square feet. It is certified testing by independent laboratories and comes with a lifetime warranty.