Sina Optical Co., Ltd.
- Maker of various magnifying glasses, lenses, prisms and mirrors for educational use.
- http://www.magnifier.co.kr/

Duk Shin Precision Mfg. Co., Ltd.
- Builder of plastic injection molds for manufacturing applications. Locations in Gunpo City, Hwaseong County and Jangseong County.
- http://www.dukshin.co.kr/

Cera E and C Co.,Ltd.
- Maker of ceramic fibers, heaters, bricks, burner tiles, refractory anchors and installation, and kilns.
- http://www.ceraenc.com/

NK Co., Ltd.
- Manufacturer and system integrator of fire protection equipment and high-pressure gas cylinders. Headquartered in Busan, with operations in Seoul and overseas. [Korean, English, Chinese, Japanese]
- http://www.nkcf.com/

Korea Aerospace Industries, Ltd.
- Manufactures aircrafts and satellites. Headquartered in Seoul with locations in Daejeon and Gyeongnam province. [Korean, English]
- http://www.koreaaero.com/