Etymotic Research ER23-HF3-BLACK-I HF3 In-Ear Headset with 3-Button Remote Control for iPod, iPhone, iPad (Black) Made for Apple iPod, iPhone and iPad functionality Close-proximity high sensitivity microphone. Achieves highest output sensitivity in its class with 105 dB SPL sensitivity at 1 kHz at 0.1 mV. 85%+ response accuracy from 20 Hz - 15 kHz. AccuDriver(TM) high performance, precision matched, balanced armature drivers. ACCUFilter(TM) User-replaceable filters that protect the balanced armature drivers. Includes an assortment of noise-isolating ACCUFit eartip options to ensure proper seal and comfort. CUSTOMFIT option available. The free Awareness! by Etymotic app that was offered with iOS-compatible headsets has been discontinued; however, a Pro version with extended features of the original app is available for purchase in the app store.