The resilient glass, which is comprised of 11-layer materials, is introduced from polarized lenses produced by an American company Polaroid.
The flip-up lens is a material that blocks 100% of all UVA, UVB, UVC and harmful blue light

PC interface supported:USB      
Digital formats supported: MP3/WMA      
Signal-to-noise ratio:87.2dB      
Playback Modes:Random play      
External hard drive function: Yes      
Audio Additional features:Auto-power off      
Earphones type: Binaural      
Mfr estimated battery life :5hours continuous      
Charging  Time:3hours continaully       
Battery tape/capacity: Built-in Lithium lon Polymenr/3.7v,150mAh      
Maximum imput power rating:5VDC,150mA      
Voice output power:55mW      
Voice output frequency:20Hz-20Khz      
earphone impendance:16 Ω*2      
Memory Flash:128MB-4GB