Features: 1 Turn any hollow core into a speaker: This bone conduction speakers are the smallest 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 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 of sound effects 3 Portability: This product is small in size light in weight, which is very convenient to carry around 4 Small but powerful speakers: If you find the right object for your bone conduction horn, speakers can be very powerful, reaching 115 decibels allowing you to customize the sound quality It is recommended to place thin objects such as halloween plastic boxes or buckets 5 Multifunctional speakers: You can use bone conduction speakers to listen to music, podcasts, st-alone phone conversations or conference calls, play games or , even enjoy the experience of game sound Bone conduction speakers also function as fm radios, allowing you to listen to music follow podcasts : Capacity: 400mAh Function: Bone Conduction Speaker, FM Wireless ver: 5 0, A2DP, HFP Wireless Stereo supported FM radio build-in Bone Conduction transducer: 3Watt Frequency range: 120Hz-16kHz High sensitive microphone build-in Battery: 400mAh Polymer Battery Charging port yo=C charging port (not compatible fast charge) Suggest to use FM function outdoor, plug in USB cable as well Material: Metal colour: silver Package Contents: 1 x Bone Conduction Speaker 1 x Charging cable Only the above package content, other products are not included Note: Light reflection different displays may cause the color of the item in the picture a little different from the real thing The measurement allowed error is and\/- 1-3cm