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 hollow objects into functional speakers. 2. Different sounds with different surfaces: Utilizing bone conduction technology, this speaker delivers a customizable o experience. Placing it on various surfaces such as glass, wood, plastic containers, photo frames, or headphones can produce distinct sound characteristics. 3. Portability: Lightweight and compact design makes it convenient to carry and use anywhere. 4. Small but powerful: When used with suitable materials like thin plastic or hollow containers, the speaker can deliver strong o output, reaching up to 115 decibels, with adjustable sound quality. 5. Multifunctional use: Supports music playback, podcasts, hands-free calls, conference calls, and gaming o. Built-in FM radio function allows for radio reception and o streaming. Specifications: Capacity: 400mAh Functions: Bone Conduction Speaker, FM Radio Wireless Version: 5.0, A2DP, HFP Stereo o Support: Yes Built-in FM Radio: Yes Bone Conduction Transducer: 3Watt Frequency Range: 120Hz - 16kHz Built-in High-Sensitivity Microphone: Yes Battery: 400mAh Polymer Battery Charging Port: USB-C (does not support fast charging) Note: For optimal FM performance, use outdoors and connect the USB cable. 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.