Crystal Radio Earphone, High Impedance, 3.5mm Description High impedance crystal earphone - very sensitive and works great with crystal radios. Has 3 a foot cord and miniature (3.5 mm) plug. Features: High impedance crystal earphone - very sensitive and works great with crystal radios Has 3 a foot cord and miniature (3.5 mm) plug. Product Details: Brand: AmplifiedParts Color: Tan Form Factor: In Ear Connectivity Technology: Wired Wireless Communication Technology: RF Brand: AmplifiedParts Included Components: Earphone Age Range (Description): Adult Model Number: Piezo-earphone-3.5mm Number of Items: 1 Connectivity Technology: Wired Wireless Communication Technology: RF Headphones Jack: 3.5 mm Jack Form Factor: In Ear Ear Placement: In Ear Material: Plastic Item Weight: 4 Ounces Color: Tan Special Feature: Mini (3.5 mm) plug, 3 foot cord, Sensitive, High impedance Cable Feature: Retractable