According to Project Manager David T. Chapman, AEC has fabricated miniature electronic data recorders that have overall dimensions on the millimeter scale but feature nanoscale materials and circuitry. For example, one device, which measures just 3 mm along one side and can store thousands of readings, contains a solar cell, batteries, temperature and pressure sensors, a data processor, and other components. The pressure sensor has nanoscale diaphragms, and the battery features a nanostructured silicon anode, which enables it to hold charge at reservoir temperatures (130 °C) that cause most batteries to quickly fail.