FiiO FD1 In Ear Monitors The FiiO FD1 features powerful beryllium plated dynamic driver unit on each side. Beryllium is a rich and premium material that is very lightweight and thin yet rigid. It ensures swift movement of the driver coil and provides unmatched sound quality output. Drivers in mid to high-level IEMs usually have beryllium coated or beryllium material driver units. The driver has a two-way magnetic circuit that creates better magnetic flux and ensures an energetic sound output with crisp clarity. FiiO Patented Balanced Pressure Relief Technology The earpieces in FiiO FD1 features patented balanced pressure relief technology. It ensures the pressure due to the driver coil movement is in a balanced state and provides a distortion-free sound output. Celluloid Faceplate Design The earpieces in FiiO FD1 have celluloid style unique faceplate design. The faceplates have a rich layered celluloid design that complements the unique texture and glossy design of the earpieces. They are very lightweight and sit firmly into the ears providing a comfortable fit to the users. High-Quality Bundled Cable The FiiO FD1 comes with a 4-Strands high-grade single crystal copper cable. Each strand has 30 cores so there is a total of 120 cores. Each wire is insulated well from each other ensuring high-quality audio signal transmission without any interruptions providing unmatched sound signal quality with lifelike vocals and rich deep bass.