Newly Designed Updated Model for 2022 - Featuring a Brass Diaphragm and All Soldered Wire Connections Redesigned to eliminate connectivity issues and increase reliability allowing you to make electronics projects like Crystal or Transistor Radios without concern for issues plaguing lower quality models High 20,000 ohm impedance with resistance over 20 million ohms and a capacitance of 15,000 pf Rated Sensitivity of 57db at 1KHz in the frequency range from 200 to 8,000Hz New Black Wire Upgraded Piezoelectric Earphone with Classic style highly sensitive molded earpiece and 42-in twisted wire with pre-tinned bare wire connections