In-Ear Headphones with in-Line Microphone with TRRS 3.5 mm Jack Plug (4 contacts) Compatible with Apple iPhone, iPhone 3G/3Gs and iPhone 4/4s Specifications Type: Earphone with in-line Microphone Speaker Size: 10 mm Diam. Impedance: 32 Ohm Frequency Response: 20 Hz ~ 20 KHz Rated Power Input: 3 mW Sensitivity: 58 dB+/-2 dB (1 KHz) Cord Length: 120 cm Connectors: Audio and Microphone Input: Single 3.5 mm TRRS Jack Plug with four contacts NOTE: Verify in your audio device documentation the 3.5 mm Jack Socket conform to standard measures and is compatible with four contacts TRRS connectors. The in-line microphone can be used as a mobile phone headset exclusively on models that support 3.5 mm TRRS connectors.