This product is a voice amplifier. It features 2200mAh batterry for long time use. It amplifys your voice and relieve your throat stress. The amplifying sound is clear, crisp, no noise and no distortion, loud enough for daily use. This product is the best protector for your throat. Features -Color: White-Material: Metal-Size: About 9.00X8.40X2.80cm/3.54X3.30X1.10inch-Note: Powered by USB cable- The amplifying sound is clear, crisp, no noise and no distortion.- Compact size and light weight. You can use the back clip to fix it on your belt or pocket. You can also use waistbelt to tie it around your waist or it on your neck.- Built in 2200 mAh rechargeable lithium battery. The working time is longer.- Supports TF (Micro SD) playing MP3 audio playing: Repeat single tune, loop all music and switch songs.- The wired headworn microphone is adjustable. You can adjust the distance between your mouth and the mic.- Suitable for teacher tour guide, etc., has a wide range of applications Specification -Distortion rate: 0.03%-Output power: 3W-Rated voltage: ≤36V-Covered space: 1000-Standby time: 72 hours (10 days)-Charging time: 3 hours-Battery Capacity: 2200mAhPcking list: 1 x amplifier1 x microphone1 x strap1 x charging line