of Polyethylene plastic. The two major types of base construction are extruded and sintered. An extruded base is a basic, low-maintenance design which basically consists of the plastic base material melted into its form. A sintered base uses the same material as an extruded base, but first grinds the material into a powder, then, using heat and pressure, molds the material into its desired form. A sintered base is generally softer than its extruded counterpart, but has a porous structure which enables it to absorb wax. This wax absorption (along with a properly done 'hot wax'), greatly reduces surface friction between the base and the snow, allowing the snowboard to travel on a thin layer of water. Snowboards with sintered bases are much faster, but require semi-regular maintenance and are easier to damage. The bottom edges of the snowboard are fitted with a thin strip of steel, just a couple of millimeters wide. This steel edge allows the board to grab or 'dig into' hard snow and ice (like the blade of an ice skate), and also protects the boards internal structure. The top of the board is typically a layer of acrylic with some form of graphic designed to attract attention, showcase artwork, or serve the purpose similar to that of any other form of printed media. Flite Snowboards, an early designer, pressed the first closed-molded boards from a garage in Newport, Rhode Island, in the mid-1980s. Snowboard topsheet graphics can be a highly personal statement and many riders spend many hours customizing the look of their boards. The top of some boards may even include thin inlays with other materials, and some are made entirely of epoxy-impregnated wood. The base of the board may also feature graphics, often designed in a manner to make the board's manufacturer recognizable in photos. Snowboard designs differ primarily in: Length – Boards for children are as short as ; boards for racers, or "alpine" riders, are as long as . Most people ride boards in the range. Board length used to be judged by the height of your chin. If a board held next to the frontside of your body came to your chin then it was an acceptable length. Due to the development of new technologies and board shapes, people can now ride a wider range of board sizes. Rather, the length of a snowboard corresponds mainly to the style, weight,