Thank you for viewing our products. Instant purchase is welcome. Thank you. 【About Kiwi Ears】 At Kiwi Ears, our driving force is the pursuit of superior audio reproduction. We perfectly combine technological innovation and excellent tuning strategies. Especially to meet the demands of audiophiles and recording studio engineers, we uncompromisingly develop professional in-ear monitors to provide a wonderful musical presence. Also, our engineers do not adopt the general headphone development process, and all drivers are handmade by the engineers. Users do not need to worry about the quality of the drivers, but only get a wonderful music experience. We are Kiwi Ears, bringing unprecedented musical experiences to audiophiles. 【Excellent Bass Expression】 The bass driver of the Kiwi Ears Quartet adopts a new coaxial dual dynamic diaphragm design. The innovative driver design employs dual 10mm titanium diaphragm dynamic drivers, and all drivers are driven by independent dual magnetic flux. This dual dynamic diaphragm supports passive phase synchronization to avoid sound waves canceling each other out. This new subwoofer design releases a tight, fast, deep, and very well-extended sub-bass kick than any previous woofer design. The Quartet is Kiwi Ear's answer for everyone looking for a fun in-ear monitor, providing all the quality bass you need. 【Natural Sound】 The Kiwi Ears Quartet inherits Kiwi Ears' natural and balanced tuning characteristics. To meet the demands of professional musicians and audio engineers, the sound quality of the Kiwi Ears Quartet is like a recording studio ear monitor. The Kiwi Ears Quartet adopts a 3-way structure, achieving complex layering, and effectively reducing THDN. The bass of the Kiwi Ears Quartet is limited to the sub-bass frequency band. The peak value from 20Hz to 200Hz is 8dB. From 200Hz to 800Hz, within that