Koss designs and sells stereo headphones under its own brand and private label. Music listening headphones make up roughly 84% of sales, with the remainder going to communications, education, metal detection, and OEM applications. Koss sells through a broad mix of channels including U.S. and international distributors, national retailers, grocery stores, electronics retailers, specialty audio stores, schools, prisons, and DTC via its website and Amazon. Amazon DTC alone accounted for roughly 19% of FY25 net sales, making it the single largest customer. The top five customers collectively represented about 50% of FY25 net sales. The U.S. is Koss's largest market at roughly 71% of FY25 net sales, with Sweden and Czech Republic as the next largest international markets. Koss sources most products from contract manufacturers in China and Taiwan, while maintaining a manufacturing facility in Milwaukee. Koss earns its margin on the spread between sourcing costs and selling prices, with profitability driven by unit volume, product mix (branded vs. private label), and pricing power relative to sourcing and freight costs. Koss also runs an active IP enforcement program, pursuing patent infringement lawsuits since 2019, though patent licensing is not a primary revenue driver. Koss positions itself on brand heritage — it introduced the first personal stereo headphone in 1958 — and focuses on channels like schools and prisons that larger competitors may deprioritize.