[CCA CRA+ Full Upgrade] Strengthen the power of lower frequencies than CRA and has a wider frequency. It also has improved the experience of high frequency sounds, and brings you a better hearing banquet. Re-structure the trapper: In order to achieve an auditory improvement of the resonance peak, the structure of the rapper, further improve the sound quality, and bring the sound to the spot. (New Coil Upgrade) The 0.4 inch (10 mm) large coil arrangement with a patented ultra-thin polymer composite vibration membrane, and the 0.06 inch (0.15 mm) magnetic gap is beneficial for lower distortion rate. 0.01 inch (0.035 mm) diameter circuit provides a stable and efficient driver vibration frequency and provides 3D immersive hearing. (Upgraded Design for Diversity) 2 PIN insert construction design, 0.75 mm standard pins, meets the diversity of HiFi upgrade. Pure silver wire material can effectively prevent winding and extend the service life.