Japanese (Famicom) cartridges are shaped slightly differently. While the NES used a 72-pin interface, the Famicom system used a 60-pin design. Unlike NES games, official Famicom cartridges were produced in many colors of plastic. Adapters, similar in design to the popular accessory Game Genie, are available that allow Famicom games to be played on an NES. In Japan, several companies manufactured the cartridges for the Famicom. This allowed these companies to develop their own customized chips designed for specific purposes, such as chips that increased the quality of sound in their games.