High-quality powered headphone lets your music with no quality loss Built-in Lithium battery with up to 25 hours of audio playback and fully portable Smart switch, insert the headset automatically, without manual switch Power boost, Bass boost, Sound Quality compensation The SD05 PLUS is the perfect companion to modern smartphone and laptop computers that needs some help in the audio department. Power to 130mW, the mobile phone audio output power increase about 10 times, reach most headphones best power demand range SD05 PLUS exclusive tuning style, with automatic adjustment of low-frequency dynamic gain adjustment module to enhance bass performance Reverse Charge Pump Circuit Design - Effectively improve the audio sense of hearing, compensation for mobile phone sound quality Plug-n-Play Instant Audio Improvement SD05 PLUS uses the all-intelligent headphone amplification program, without any operation, detects the headset insertion auto-start, which is shown by the indicator light. Small, Portable, and Easy to Use SD05 PLUS is only a lighter size, you can easily put into the pocket, easy to carry It is for mobile phones, laptop computers, headphones, speakers, car Audio and other equipment. 10 Min charge, HIFI All Day Li-poly battery provides approximately 22 hours of play time on a full charge. It only takes 10 minutes to fully charge. Specifications - Frequency Response: 15~27000Hz - Earphone Impedance: ≤32 Ohms - THD+N: 0.006% (1kHz) - SNR: 90dB (A-Weighted) - Output Power: >130mW (≤75 Ohm) - Battery: 180mAh, approx. 22H usage - Dimensions: 1.65" x 1.57" x 0.37" - Weight: 0.71 oz