1: Realize the most intimate contact with the ears, greatly reduce the leakage of sound, this advantage has two directions;
(A: increase the texture and volume of the low frequency; b: increase the performance of the music details) At present, the low-end earplugs mostly use a, while the high-end earplugs mostly use b.
2: Reduce the interference of external noise on listening to music (ie: in a noisy environment, you can enjoy music at a relatively low volume without being affected.);
