Features: 1. Turn any hollow core into a speaker: This bone conduction speakers are the smallest and most versatile bone conduction speakers in the world, allowing you to have a different but still great sound experience in any environment. Turn any void into a speaker anytime, anywhere. 2. Different sounds with different surfaces: This speaker uses bone conduction technology to give you a diy sound experience. You can test and enjoy different sounds - almost like using different instruments. Putting it on different surfaces like glasses, guitars, kraft paper boxes, plastic storage boxes, photo frames, sports headphones or even dashboards can give you a variety of sound effects. 3. Portability: This product is small in size and light in weight, which is very convenient to carry around. 4. Small but powerful speakers: If you find the right