<b>Patent Technology</b><br>Suspension Type Low Frequency Resonant System Special acoustic design structure that lets air compress and expand to release energy.<br><br>Low Frequency Tracking Supports real-time volume compensation. This means that when you reduce the volume, you can still experience a good resonating sound at low frequency level.<br><br><b>Key features:</b><br>- Listening music wirelessly via Bluetooth® or wired via cable connection.<br>- Bluetooth® Specification 3.0, operating range up to 10 m<br>- Integrated microSD-card slot for MP3 playback<br>- Easy BT connection by NFC (NearFieldCommunication) possible<br>- Remote control features<br>- Built-in rechargeable Li-ion battery usage up to 4-5 Hours This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 4330-01-347-4687, indicating validated use in U.S. government and defense logistics supply chains.