Two of these five point at a measurement framework for their noise-cancelling claims, and the difference between them is worth knowing. Apple writes, in bullet 9 of its own listing, under a heading that reads LEGAL DISCLAIMERS, that the 1.5x improvement is measured when tested in accordance with IEC 60268-24. That is a numbered standard, in a bullet, in the place a buyer reads.
Sony also cites something. In gray type at the foot of one gallery photograph it says that the noise reduction is according to research by Sony Corporation, measured using IEC-compliant guidelines, for the top 10 brands by market share of the headband-style wireless noise-cancelling market, as of June 1, 2026. Read that again slowly: the tester is Sony, the standard is unnumbered, and the peer group is defined by market share rather than by acoustics.
Neither is a third-party certification, and there is no register for noise cancelling the way there is for water use or for medical devices. The Bluetooth qualification listing is behind a login and a radio grant applies to every product that ships, so neither separates anything. Absent a register, the best a reader can do is prefer the maker that says how it measured, and notice which surface it chose to say it on.