The customer wanted to combine Lack shelves and Expedit Shelving Units to have a wall unit. She decided to use the smaller Expedit Shelf as a bench and hang the Lack shelf above it. The biggest challenge was securing the larger Expedit Shelving Unit. I used a 2×2 pine cleat secured by drilling through wood studs for the shelf to rest on then used the included 4 wall mounting brackets to drill through studs to secure it to the wall. I believe the final product looks like it was meant to go together.