Transistor packages are made of glass, metal, ceramic, or plastic. Houses may be clad in siding or faced with ceramic tile. The spheres can be made from several materials, including glass, ceramic, and polymers. Most bicycle hubs use steel or ceramic ball bearings. This plate is produced from specially formulated ceramic and metal alloys. They are generally piston engines with combustion chamber parts lined with ceramic thermal barrier coatings. Supported spindles spin on surfaces such as bowls that are usually ceramic or wooden. Petrie developed the system of dating layers based on pottery and ceramic findings. These are a hybrid of metal and ceramic crowns. It consisted of an arrangement of metal plates, ceramic blocks and open space. The mechanism consists of a plastic tank hidden inside the typical ceramic cistern. Ceramic and metallic diaphragms are used. SnO has been used as pigment in the manufacture of glasses, enamels and ceramic glazes. It possibly consisted of special materials including ceramic or high density uranium alloys. Silica is used to make fire brick, a type of ceramic.