Koken Ltd., together with its subsidiaries, produces and sells occupational personal protective and environmental quality improvement equipment in Japan. It operates in Mask-Related Business, Environmental-Related Businesses, and Other Businesses segments. The company offers clean air solutions, including KOACH, a clean zone creator; KOKENLAMINAR, a push-pull ventilation system; and surgical masks sold at a drug store and masks for use in natural disasters and emergencies. In addition, the company offers respirators for industrial use, including particulate respirators, powered air-purifying respirators, supplied air respirators, chemical cartridge respirators, and gas masks; respirators for general consumers; and protective clothes, earplugs, face shields, etc. The company was founded in 1943 and is headquartered in Tokyo, Japan.