It measures 158 centimetres (5 feet, 2 inches) tall, and weighs 43 kilos (95 pounds) - including a battery pack. The robot's shape and joints are based on the 1997--1998 Japanese body dimension database. The HRP-4C has a realistic head, and the average figure of a young Japanese female. It can move like a human and responds based on speech recognition. It is capable of recognizing ambient sounds and, by using the vocal synthesizer Vocaloid, can sing. The software that operates the robot is developed on the basis of Open Robotics Platform (OpenRTP), including OpenRTM-aist and OpenHRP3. Recent upgrades have allowed HRP-4C to mimic human facial and head movements, as well as execute dance steps, resulting in the most realistic performance yet at Tokyo's Digital Content Expo in 2010.