Features: 1. Turn any hollow core into a speaker: These bone conduction speakers are compact and versatile, allowing you to enjoy a unique o experience in various environments. Transform hollow objects into functional speakers with ease. 2. Different sounds with different surfaces: Utilizing bone conduction technology, this speaker delivers varied sound outputs depending on the surface it's placed on. Experiment with glasses, guitars, paper boxes, plastic containers, photo frames, headphones, or dashboards for diverse acoustic effects. 3. Portability: The device is small and lightweight, making it convenient to carry. 4. Small but powerful speakers: When used with suitable materials, these bone conduction speakers can produce strong sound output up to 115 decibels, offering customizable o quality. Thin materials such as plastic boxes or buckets are recommended for best performance. 5. Multifunctional speakers: Use the bone conduction speaker for music, podcasts, phone calls, conference calls, gaming, and immersive o experiences. The speaker includes an FM radio function for music playback and podcast listening. Specifications: Capacity: 400mAh Function: Bone Conduction Speaker, FM Wireless version: 5.0, A2DP, HFP Wireless Stereo supported FM radio built-in Bone Conduction transducer: 3Watt Frequency range: 120Hz-16kHz High sensitive microphone built-in Battery: 400mAh Polymer Battery Charging port: USB-C charging port (not compatible with fast charging) Recommended to use FM function outdoors; plug in USB cable for best results. Material: Metal Color: Silver Package Contents: 1 x Bone Conduction Speaker 1 x Charging Cable Only the items listed above are included; other products are not included. Note: Light reflection and different displays may cause slight color variations between the item and the image. Measurement error allowed is +/- 1-3cm.