Highly sensitive microphone amplification, ALC automatic level control, up to 1000 times amplification, can amplify weak sounds, directly drive headphones for listening, and can be connected to mobile phones for recording, and the interfaces are all 3.5mm;
Built-in lithium battery, which can be using a mobile phone charger. It can be used continuously for 20-30 hours when fully ;
To achieve good results, you need a high-directional microphone. You can make your own or buy one. Please search online.

Input and output interface: 3.5mm;
Mobile phone interface: 3.5mm four-pole
Microphone gain: 40db/60db switch
Headphone amplifier power: 105mwx2/16 ohms
Built-in lithium battery, capacity 300mah
Power interface: 5V
socket specification: 3.5x1.35
size: About 6.3 x 5.2 x 2.2cm
Material: plastic+metal
colour: black

Package Contents:
1 x amplifier
1 x Charging Cable
1 x phone connect cable