KOSS was founded in 1958. They launched the first STEREO stereo headphones in 1958 and continued to launch various forms of headphone products. The most famous of which is the Porta Pro, a portable headphone launched in 1984. When Porta Pro was launched that year, it became popular around the world riding on the Walkman craze. Its excellent quality and sound quality were loved by consumers. Even today, Porta Pro is still a best-seller in the market with its original design.