Features: 1. Turn any hollow core into a speaker: These bone conduction speakers are compact and versatile, enabling a unique audio 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 placing it on various surfaces such as glass, wood, plastic containers, photo frames, or metal objects to achieve different acoustic effects. 3. Portability: Designed to be small and lightweight, this speaker is easy to carry and ideal for on-the-go use. 4. Small but powerful: When paired with suitable resonant objects, the speaker can produce strong sound output, reaching up to 115 decibels. For best results, use with thin, hollow materials like plastic containers or buckets. 5. Multifunctional use: Enjoy music, podcasts, phone calls, conference calls, gaming audio, and immersive sound effects. The built-in FM radio allows for additional entertainment options. 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 and connect USB cable during use. Material: Metal Color: Black Package Contents: 1 x Bone Conduction Speaker 1 x Charging Cable Note: The actual product color may vary slightly due to lighting and display differences. Size measurements may have a 1-3cm variation.