Features: 1. Turn any hollow core into a speaker: These bone conduction speakers are the smallest and most versatile bone conduction speakers in the world, allowing you to enjoy a unique sound experience in any environment. Transform any hollow surface into a speaker anytime, anywhere. 2. Different sounds with different surfaces: This speaker uses bone conduction technology to deliver a customizable audio experience. You can test and enjoy varied sound outputssimilar to using different instruments. Placing it on surfaces such as glasses, guitars, paper boxes, plastic containers, photo frames, headphones, or dashboards creates a range of acoustic effects. 3. Portability: The product is compact and lightweight, making it easy to carry. 4. Small but powerful speakers: When paired with the right object, these bone conduction speakers can produce strong audio output, reaching up to 115 decibels, with customizable sound quality. It is recommended to use thin materials such as plastic boxes or buckets for optimal performance. 5. Multifunctional speakers: Use the bone conduction speaker for music, podcasts, phone calls, conference calls, gaming, or movie playback. It also functions as an FM radio, enabling music listening and podcast streaming. 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: 120Hz16kHz Built-in High-Sensitivity Microphone Battery: 400mAh Polymer Battery Charging Port: USB-C (not compatible with fast charging) Recommended to use FM function outdoors; connect USB cable during use. Material: Metal