CFR › Title 40 › Part 211 › §211.20540 CFR §211.205Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗Copy link(a)Any manufacturer wishing to make claims regarding the acoustic effectiveness of a device, other than the Noise Reduction Rating, must be prepared to demonstrate the validity of such claims.(b)[Reserved]