Onyx: Slatestone Flat Panel: 15 1/2" high, 43" wide, 1 3/4" thick: 4 pieces per box: 16.4 sqft coverage per box: sold by the full boxProduct Description The Onyx Slatestone Flat Panel gives your wall the look of real stacked stone without any of the weight or mess. The panels interlock and fasten directly to the wall using a starter strip which you can purchase separately. All you need to do is line them up and fasten them with screws. They then sit tightly on the wall, making it easy to keep things straight as you build. No special tools are needed and there is no mortar or messy