Features: 1. Turn any hollow core into a speaker: These bone conduction speakers are compact and versatile, enabling a unique sound experience in various environments. Transform any hollow surface into a speaker anytime, anywhere. 2. Different sounds with different surfaces: Utilizing bone conduction technology, this speaker delivers a customizable o experience. Experiment with various surfaces such as glass, wood, plastic containers, photo frames, or headphones to enjoy distinct sound effects. 3. Portability: Designed with a small size and lightweight build, this speaker is easy to carry and use on the go. 4. Small but powerful: When attached to suitable materials like thin plastic or wood, the speaker can produce strong o output up to 115 decibels, allowing for personalized sound quality. 5. Multifunctional use: Enjoy music, podcasts, phone calls, conference calls, and gaming o. Supports FM radio functionality for listening to broadcasts. Specifications: Capacity: 400mAh Function: Bone Conduction Speaker, FM Wireless version: 5.0, A2DP, HFP Supports wireless stereo Built-in FM radio Bone Conduction transducer: 3Watt Frequency range: 120Hz-16kHz Built-in high-sensitive microphone Battery: 400mAh Polymer Battery Charging port: USB-C (not compatible with fast charging) Recommended to use FM function outdoors with USB cable connected Material: Metal Color: Black Package Contents: 1 x Bone Conduction Speaker 1 x Charging Cable Note: Light reflection and display differences may cause slight color variations between the image and the actual item. Measurement tolerance: +/- 1-3cm.