Features: 1. Turn any hollow core into a speaker: These bone conduction speakers are compact and versatile, allowing you to experience sound in a unique way across various environments. Use them with different hollow objects to create audio experiences on the go. 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 enjoy varied sound effects. 3. Portability: Lightweight and compact design makes it easy to carry and use anywhere. 4. Small but powerful speakers: When paired with the right surface, these speakers can produce strong sound output up to 115 decibels, with customizable sound quality. Best performance is achieved with thin, resonant materials like plastic containers or buckets. 5. Multifunctional speakers: Ideal for listening to music, podcasts, making hands-free phone calls, participating in conference calls, playing games, or enhancing gaming audio. The built-in FM radio function allows you to tune into radio stations and enjoy live audio content. 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 performance Material: Metal Color: Silver Package Contents: 1 x Bone Conduction Speaker 1 x Charging Cable Note: The product image may slightly differ in color due to lighting and display settings. Measurement tolerance: +/- 1-3 cm.