Received on December 12th and used once for testing. It's almost new ✨. It's not bone conduction. It's an ear cuff type, so it doesn't completely shut out external sounds, making it suitable for use while riding a bicycle or during remote work (^ ^) I used it during remote work, and it was fine without completely blocking out external sounds, so I'm selling it. Since it's almost new, I hope someone will use it (^ ^) ※Warranty can be extended up to 36 months just by adding a friend on LINE. I haven't added it, so you can add it and use it.