1、CUSTOM AND ULTIMATE: The V5i‑D dual op amp is a custom audio dedicated line of op amps, which is a ultimate edition dual op amp 2、PERFECT REPLACEMENT: Suitable for audiophiles to further improve the sound quality. The AD827SQ, AMP9922AT, MUSESO2, MUSESO1, OPA2604AP, LME49720HA etc. can be upgraded 3、WARM SOUND AND SMOOTH TRANSITION: The V5i‑D has a bold sound, warm sound quality, and smooth three band transition 4、EXCELLENT EXPERIENCE: The reductive power is outstanding, and the live listening experience is very good. Not tired after playing for a long time, and the hearing is super good 5、STABLE AND DURABLE: Dual op amp audio come with stable structure, excellent performance and long service life