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. 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. Sound quality varies when attached to different materials such as glass, wood, plastic containers, photo frames, or metal surfaces, offering a range of acoustic effects. 3. Portability: Lightweight and compact design makes it easy to carry and use anywhere. 4. Small but powerful: When paired with suitable resonant objects, the speaker can produce strong audio output up to 115 decibels, allowing for personalized sound enhancement. Thin and rigid materials like plastic containers or buckets are recommended for optimal performance. 5. Multifunctional use: Compatible with music playback, podcasts, hands-free calling, conference calls, gaming, and video watching. Built-in FM radio functionality allows for direct radio reception. Specifications: Capacity: 400mAh Function: Bone Conduction Speaker, FM Radio Wireless Version: 5.0, A2DP, HFP Supports Wireless Stereo Audio 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 (does not support fast charging) Recommended to use FM function outdoors; connect USB cable for stable reception Material: Metal