Our waterproof lid is a great addition to your 4-foot cedar deck box purchase. It is made of 1/4-inch white nylon and is a commercial grade cutting board material. You will have the beauty and durability of a Smith Family Mills, LLC cedar deck box with the waterproofness of a plastic. This product is a must for anyone ordering a cedar deck box that will fully out in the elements. Assembly is required. This product is a suggested add-on for boxes kept exposed fully to the elements. Smith Family Mills, LLC produces high-quality Eastern white cedar deck boxes, storage benches, cedar cushion boxes and refuse containers. Eastern white cedar is long-lasting and naturally rot-resistant; Smith Family Mills, LLC leaves it unfinished for natural weathering or home-finishing. The result is some of the most affordable, well-built indoor and outdoor storage on the market, all 100 percent guaranteed.