Description Reviews Make sure this fits by entering your model number. Ultra-lightweight polyester diaphragm in a tuned dynamic driver Copper-clad aluminum voice coil bring forth even the most subtle of details within the music Polyurethane cable jacket has low microphonic, and is both durable and light weight Crystal clear microphone and call/volume control buttons (volume controls not compatible with iOS devices) Superior ergonomics provides better seal with the ear, which blocks external noise more effectively Lightweight freedom for your ears. The use of an ultra-lightweight polyester diaphragm in a tuned dynamic driver gives the F1 in-ear monitor earphones a natural and relaxed tonality that works well with modern pop music. Because each in-ear unit weighs only 2.4 grams, the F1 is all but unnoticeable when worn, allowing you to enjoy music without fatigue. Special Voice Coil A lighter voice coil makes for faster transients and better overall sound quality. This exactly describes the copper-clad aluminum voice coil used in the F1, which allow sit to present a transformative listening experience by clearly bringing forth even the most subtle of details within the music. Robust and Reliable Cable Through extensive tests and evaluation of a wide variety of materials on a multitude of factors, polyurethane emerged as the material of choice for the F1's cable. Polyurethane has low microphonic, and is both durable and light weight. Its highly elastic and tough characteristics protect against scrapes and wear. Smartphone Support The F1 Gen incorporates a crystal clear microphone and call/volume control buttons. These controls not only works perfectly with the X1-II and X5-III music players, but also supports most Android smartphones. The microphone and call button works with iOS devices, but volume control does not. Superior Ergonomics The comfort and fit of an in-ear monitor is arguably just as important as its sound quality. With this knowledge, FiiO took on the challenge of making a comfortable IEM. After studying many listener ear canals, we determined that a 45-degree angled design allows the in-ear units to better and more comfortably fit the human ear canal. This design also allows the F1 to create a better seal with the ear, which blocks external noise more effectively.