Etymotic Research ER23-HF2-BLACK Earphones/Headset--Black Made to work with smartphones and tablets from Blackberry, Samsung, HTC, Motorola Mobility, HP and Apple 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 high performance, precision matched, balanced armature drivers. ACCUFilter User-replaceable filters that protect the balanced armature drivers from ear wax An assortment of noise-isolating ACCUFit eartip options to ensure proper seal and comfort. CUSTOMFIT option available Black soft-touch finish