Arauco shiplap is a brand of shiplap made by Arauco, a Chilean forestry company. It is made from Radiata pine, a softwood that is known for its strength and durability. Arauco shiplap is available in a variety of sizes and finishes, including unfinished, primed, and stained. It is a popular choice for interior wall paneling, ceilings, and other applications. The dimensions of Arauco shiplap are 9/16 inches thick, 7-1/4 inches wide, and 8 feet long. The gap between the boards is typically 1/8 inch. Arauco shiplap is a good quality product that is backed by a warranty. It is a popular choice for homeowners and builders who are looking for a beautiful and durable wood product for their projects.