New advances in materials and design have served to expand the performance of Koss products. The company's product development team and engineers look for the most innovative combinations of existing and new technologies to deliver the most exciting products possible.A portable headphone is a headphone that is used on the go. Portable headphones tend to be smaller, more lightweight, and may have features that lend themselves to listening on-the-go, like carrying cases or collapsible headbands.