YouthWhisper bone conduction headphones design for sport, such as running, workout, and hiking, bone conduction headphones transmit sound through vibration, so you can hear the sound more clearly and loudly while insert the spong earplugs in your ear, but at the same time the air can also transmit the sound, so it is not silent to the person next to you, so don't turn up the volume on bone conduction headphones to 100% if you don't want the person next to you to hear the sound