Micro Earpiece kit GSM box/bank card style for invisible communication

Details
Supper micro gsm earpiece,218 invisable earpiece,Hidden in Cap,T-shirt,Coat invisable earpiece,GSM Micro Earpiece GSM transmitter,Wireless Micro Earpiece Hidden Earphone,GSM in Ear Earpiece support 218,305 earpiece
Features:
Two way covert communication via mobile phone networks
Optimized inductive coil creates strong power for earpiece
Can support Works with Micro Nano earpeice
Built-in top sensitive 38dB microphone to pick up whisper voice
with this supper micro GSM earpiece you can hidden it in your CAP,T-SHIRT,COAT, it is best way for voice transfer in anywhere.

Specifications:
GSM Bands: 850/900/1800/1900MHz
Max transfer power: GSM900 Class4 2w,DSC1800 Class1 1W
Sensitive: -102dBm
Dual battery: 400mAh,600mAh
Working time: 400mAh working 4-5 hours,600mAh working 5-7 hours
Standby time: 15days
Volume: 3 level adjust
Working temperature: -25 degree - + 70 degree
Voltage: 3.4-4.5V
Current: 200MA
Standby current: 1MA
Compatible Earpiece: 218,305 model(we offers 305 model in default)
Installation:
A: Intall the battery to micro earpiece, plug in your ear.
B: Cut GSM SIM card to Micro SIM card(like iphone4 SIM card size), plug into the GSM module, please check the correct direction.
C: Put into you collar.
D: Press the Power Button for 3 seconds, your will listen "Power on Start" voice prompt from your earpiece.
During power on status press this button for 3 second again it will power off, you will listen "Power off" voice prompt from your earpiece
You can press voice button to adjust the volume, three level(large,middle,small), when it adjust to large volume you will listen "di,di" sound in earpiece, press to change in cycle.
Now, install finished you can phone call the SIM card number, you can listen and speak.