Can Here One be used as a hearing protection device?

No. Here One is not designed to be a hearing protection device, and we do not recommend it for use as hearing protection. Here One does block your ear canal and allow you to personalize your audio environment – which includes reducing the volume. There is, however, a limit to the amount of noise reduction that Here One can provide, and it does not prevent noise-induced hearing loss in overly loud environments or over prolonged periods of time.