Features: 
Built-in sounder, clear voice, save electricity. Wear nature and comfortable, will not oppress the ear. 

Technical Parameters: 
* Max Out: 130 ± 4dB 
* Max Gain: 48 ± 5dB 
* Harmonic Dist: ≤ 5% 
* Frequency Range: 450Hz ~ 3500Hz 
* Equivalent Input Noise: ≤ 32 dB 
* Standard Battery: AG13 button cell 
* Voltage: 1.5V 
* Current: ≤ 3mA 

Specification: 
Product Weight: 8g 
Product Size: 4.6*3.8*0.9cm 
Packing details: Paper+Plastic box 
Packing Size: 12*8.5*3.2cm 
Q. T. Y/Carton: 120PCS 
Carton Size: 52.5*31*39cm 
GW: 11Kg 
NW: 9Kg

Production license: Cantonese food drug permit Product No 200220595 
Product registration number: Cantonese food drug permit 2011 No 2460193 
Product standards number: YZB/Guangdong 0680-2010