Features: 1. Turn any hollow core into a speaker: These bone conduction speakers are compact and versatile, allowing you to enjoy a unique sound experience in various environments. Use them to transform everyday objects into functional speakers. 2. Different sounds with different surfaces: Utilizing bone conduction technology, this speaker delivers a customizable o experience. Experiment by attaching it to various surfaces such as glasses, guitars, paper boxes, plastic containers, photo frames, headphones, or dashboards to experience diverse sound effects. 3. Portability: The device is small and lightweight, making it easy to carry and use on the go. 4. Small but powerful speakers: When attached to suitable objects, the speaker can produce strong sound output up to 115 decibels, with customizable sound quality. It is recommended to use thin materials like plastic containers or buckets for optimal performance. 5. Multifunctional speakers: Use the bone conduction speaker for listening to music, podcasts, making hands-free phone calls or participating in conference calls, playing games, and enjoying immersive o. The speaker also supports FM radio functionality, enabling you to tune into radio stations and o content. Specifications: Capacity: 400mAh Function: Bone Conduction Speaker, FM Wireless version: 5.0, A2DP, HFP Supports wireless stereo Built-in FM radio Bone Conduction transducer: 3 Watt Frequency range: 120Hz - 16kHz Built-in high-sensitivity microphone Battery: 400mAh Polymer Battery Charging port: USB-C (not compatible with fast charging) Recommended to use FM function outdoors; connect USB cable during use. Material: Metal Color: Black Package Contents: 1 x Bone Conduction Speaker 1 x Charging Cable Note: Light reflection and differences in display screens may cause slight variations between the color of the item in the photo and the actual product. Measurement may vary by +/- 1-3cm.