Ceramic earphone/Crystal earpiece for Crystal Radios and other projects requiring a very sensitive high impedance earpiece. <br><br> Crystal radios will not work with modern earphones or 'earbuds' as they are designed to operate with amplified audio sources found in today's electronic devices. Crystal Earphones are used in the construction of the crystal radio and in some science experiments such as listening to electric fish.<br><br> <b>Specifications:</b><br><br> ▪ Impedance: 20,000 ohm<br> ▪ Resistance: 20,000,000 ohm<br> ▪ Capacitance: 15,000 pf<br> ▪ Sensitivity: 57db @ 1KHz<br> ▪ Frequency Range: 200 - 8,000Hz<br> ▪ Operation Temperature: -20 to 60 degree Celsius<br> ▪ Wire: 42-inch Molded twisted Wire<br> ▪ Connector: Tinned Leads for DIY Connections<br><br> <br> ***Note: These are the factory specifications and may vary <br>