Design and features:The CX 150BT has a integrated microphone, and volume, music player, and call connect/disconnect controls for paired Bluetooth devices. This model comes with four pairs of ear pieces in various sizes and a USB charging cable. The free Sennheiser Smart Control app download for Apple and Android mobile devices provides access to the on-line user manual but otherwise does not provide any device settings or features for these earphones.
Sound quality: We found the CX 150BT delivers sound quality that falls in the very good range - it reproduces music and voice very well although it does have some noticeable sonic quirks. The bass (as in bass drums, bass guitars, stand-up bass, etc.) has good impact and goes fairly deep, but lacks a bit of detail. The midrange (voices, guitars, horns, etc.) is a touch thin and hazy, and a bit grainy and etched (a bit more sharply outlined then it should be), and may get a bit harsh at higher volumes. The treble (cymbals, the upper range of violins, etc.) is extended, but a bit prominent and a touch smeared. The sound also has a decent sense of liveliness and is somewhat open--sound-wise it almost seems like you don't have anything plugging up your ears. Mixed character - warmish bass with coolish midrange and treble. The overall sound can best be summarized as fairly even but a bit sterile.
Comfort: As typical of in-ear models they produce a sense of pressure in the ear canal opening that might be uncomfortable for some. fits and stays in place with no problem for casual use for users with small, medium, and large sized ear canals, but the cable may get caught on clothing and may pull the earphones out of the ears. the sound of the earphone connecting cable rubbing on clothing may be heard through the earphones by some users depending on the clothing it's rubbing on.