May. 1984   : Oh Sung Trading Co., Ltd. Established.
Jun. 1989    : Conclude Exclusive Distributor and Agentship with                    Kett Electric Laboratory in Japan.
Feb. 1992    : Korea Kett Sales Co. Established.
Feb. 1992    : Conclude Exclusive Distributor and Agentship                        with Zeltex Inc. in U.S.A.
Aug. 1994    : Korea Kett Engineering Co., Ltd. Established.
May. 2001    : Continue..