ANC headphone manufacturers typically quote noise reduction performance in dB, measured in laboratory conditions for transportation noise spectra (aircraft, train) where ANC performs best. These figures are not directly comparable to office speech performance and are not independently certified for cognitive work environments. HIGHKA’s 35 dB acoustic performance is measured to ISO 23351-1 — the international standard specifically developed for office furniture acoustic enclosures, measuring speech level reduction in office-relevant conditions, by an independent accredited testing laboratory. The certification is independently verifiable; the test report is available on request.