An industry first for sound isolating earphones, PTH allows you to activate the VoicePort microphone and adjust levels of external sound for clarity—enabling conversation without removing your earphones. Included with the SE530 (formerly E500PTH) earphones, it is also an optional accessory for all Shure Sound Isolating Earphones. PTH is also compatible with other brands of earphones. Gold-plated connectors ensure high-quality audio 4 ft. total cable length: 2 ft. from PTH module to voiceport mic; 2 ft. from PTH module to 3.5 mm connector Attached clothing clip for optimal microphone placement 1 AAA battery included Graphical explanation of push-to-hear technology. Documentation: Manual UPC Code: 042406141536