A wall panel is single piece of material, usually flat and cut into a rectangular shape, that serves as the visible and exposed covering for a wall. Wall panels are functional as well as decorative, providing insulation and soundproofing, combined with uniformity of appearance, along with some measure of durability or ease of replaceability. While there is no set size limit for a piece of material fulfilling these functions, the maximum practical size for wall panels has been suggested to be about 0.6 to 2.4 m (2 to 8 ft), to allow for transportation.