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 audio experience. Experiment by attaching it to various surfaces such as glasses, guitars, paper boxes, plastic containers, photo frames, headphones, or dashboards to explore diverse sound effects. 3. Portability: Lightweight and compact design makes it easy to carry and use anywhere. 4. Small but powerful speakers: When attached to suitable objects, these speakers can produce strong audio output up to 115 decibels, with customizable sound quality. Thin materials like plastic containers or buckets are recommended for optimal performance. 5. Multifunctional speakers: Use for listening to music, podcasts, making hands-free phone calls, participating in conference calls, gaming, or enhancing audio immersion. The built-in FM radio function allows you to tune into radio stations and enjoy audio content on the go. Specifications: Capacity: 400mAh Function: Bone Conduction Speaker, FM Radio Wireless Version: 5.0, A2DP, HFP Supports Wireless Stereo Built-in FM Radio Bone Conduction Transducer: 3Watt 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 for stable performance Material: Metal Color: Silver 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 shown in images and the actual product. Measurement may vary by +/- 1-3cm.