Crystal Earphone
Piezoelectric earphones also known as crystal earphones are the most sensitive earphones. In fact they are at least 10 times more sensitive than very sensitive magnetic earphones, dynamic earphones, and electrostatic earphones. Sensitive earphones have a very high impedance, which is measured in ohms.
Crystal Earphones are used in the construction of the crystal radio and in some science experiments such as listening to electric fish.
SPECIFICATIONS:
Impedance: 20K ohm
Capacity: 15,000 pf
Sensitivity: 57 dB at 1KHz
Frequency Range: 200 ~ 8000 Hz
Operation Temperature: -20º to 60º Celsius
Cord: 3ft twisted cable.