Casio Computer Co., Ltd. is a multinational electronics manufacturing company headquartered in Shibuya, Tokyo, Japan. Its products include calculators, mobile phones, cameras, musical instruments and watches. When Casio was founded, it was known for its electronic and scientific calculators. Today, Casio is most commonly known for durable, large sized watches. Especially popular are its dual function (LCD and analog) watches, some of which, including Wave Ceptor and Pro Trek / Pathfinder series, receive radio signals daily from an atomic clock to keep accurate time. The G-Shock range of shock resistant watches, is also quite popular, with the 1983 G-Shock DW-5600C being highly sought-after by collectors.