Usage Tips: Features: 1. Turn any hollow object into a speaker: These bone conduction speakers are among the smallest and most versatile in the world, delivering a unique yet high-quality sound experience in any environment. Transform everyday hollow objects into functional speakers—anytime, anywhere. 2. Variable sound output based on surface material: Using bone conduction technology, this speaker enables customizable audio experiences. Mount it on different surfaces—such as eyeglass frames, acoustic guitars, cardboard boxes, plastic containers, picture frames, or vehicle dashboards—to explore varied acoustic characteristics. 3. Portable design: Compact and lightweight for easy transport and on-the-go use. 4. High-output performance: When paired with an appropriate resonant surface (e.g., thin plastic containers or buckets), the speaker can produce sound up to 115 dB, offering adjustable sound quality. 5. Multi-functional use: Supports music playback, podcasts, hands-free calls, conference calls, gaming audio, and FM radio reception. Specifications: Battery Capacity: 400 mAh Bluetooth Version: 5.0 (supports A2DP, HFP) Wireless Stereo Audio: Supported Built-in FM Radio: Yes Transducer Power: 3W Frequency Response: 120 Hz – 16 kHz Built-in Microphone: Yes, high-sensitivity Battery Type: Polymer lithium-ion Charging Port: USB-C (not compatible with fast charging) Recommendation: For optimal FM radio performance, use outdoors and connect the USB cable during operation. Material: Metal Color: Silver Package Includes: 1 × Bone Conduction Speaker 1 × Charging Cable Note: Color appearance may vary slightly due to lighting conditions and screen settings. Dimensional tolerance: ±1–3 cm.