High quality professional music speaker keep the voice always in purity. <br /><br />Technical specification: <br />Drivers: 57mm speaker X 2<br />Transducer type: dynamic<br />Bluetooth version: V4.1<br />Frequency range: 2.4GHz-2.48GHz<br />Operating distance: up to 10m (free space) <br />Bluetooth profiles: A2DPAVRCPHSPHFP<br />Impedance: 16 <br />Frequency response: 20Hz-20kHz<br />Sensitivity: 110dB<br />Distortion:<0.1%(THD) Talk time: up to 45 hours<br />Standby time: up to 1625 hours<br />Charging time: about 2 hours<br />Operational temperature: -10 to 50 C<br /><br />Product introduction:<br />1.Iconic powerful bass resonance of Bluedio: Unexpected 57mm ultra-large dynamic drivers｣ｬstyle housing｣ｬ with iconic Bluedio surging low-frequency shock｣ｬ let you feel the bass resonate deep in the chest｣ｬ enjoying the best sound quality. Clear and transparent bass｣ｬ mids and highs｣ｬ fully exposed to all the details of song｣ｬ you can hear what the artists really want you to hear｣ｬ Coldplay or Linkin Park concerts are simply playing around your ear.<br />2.Ultra-long operation and carefree calling from Bluetooth 4.1: With robust high speed CPU of Bluetooth 4.1 operating system｣ｬ comes with ultra-long 40 hours music｣ｬ 45 hours talk and 1625 hours (around 67 days) standby time｣ｬ the same battery｣ｬ decrease up to 40% power consumption compare to Bluetooth 4.0. Acoustic echo cancellation and noise reduction effectively reduce ambient noise while talking｣ｬ make far-end listen