I love this set, I easily prefer it over other sets i have.
The punchiness of the bass and the clear and airy treble are amazing, the shell is small, light, and very comfortable, the cable is too stiff around the ear for my liking, but that's the only downside i found, at this price this set is an easy recommendation.
The Tangzu YuXuan Ji is simply one of the finest sounding IEMs in the $50.00 price range in audio. The Bass is tactile, resolving, punchy, and present in sub and mid. Midrange is clear, concise, incisive, and balanced. The treble is extended, incisive, airy, and tonally accurate. The soundstage is quite orbital and spatial cues are above average thanks to the open back design. Imaging and technicalities are also first rate. Maybe the only drawback are the lower mids and vocals can lack some body, but that's such a quibble, since throwing some tubes at it or r2r, and it sings like a bird. Fly bird fly! This IEM has wings! Literally!
Brilliant quality of all items. Excellent customer service and support. Postage costs were reasonable and arrived on time.
I didnt got them yet?
An excellent open back IEM which can compete with significantly higher priced options such as the LETSHUOER S12. The extremely small size makes it excellent for people with smaller ears or protruding ear cartilage. The shipping from Tangzu was very fast and it was professionally packed.