Maybe this iem review is a bit late but this is my first review of an in-ear monitor product and i am quite new to this audiophile hobby and i will try to give my honest and subjective opinion. I kindly apologize for any mistakes in this review.

Disclaimer :
I got this unit by my own purchase and this review is not affiliated by Moondrop nor paid by anyone or anyway.

Moondrop quarks is the cheapest entry level iem offered by moondrop in a classic bullet style shape. Unboxing and accessories are okay for the price at 12 usd. The housing itself has a transparent plastic shell that looks good but feels like cheap and easily damaged (maybe i'm just nitpicking). The cable is quite easily tangled and the eartips provided are just average.

The Sound :

Bass : Bass is light but present with average weight midbass. I could clearly hear the sub bass on EDM or other sub bass heavy tracks. Bass is quite fast in speed an decay, overall the quality is good and above average for the price.

Mid : The mids are star of the show, it's a mid-centric iem. While listening to pop songs like Taylor Swift her vocal is clear and forward without feeling shouty and harsh even at higher volumes. String instruments like guitar sound nice and have good timbre but placed behind the vocals.

Treble : Treble is smooth and rolls off pretty quick as seen in the graph, the details revealed are just okay for the price itself.

Soundstage : It feels just around or in my head in circular, nothing exceptional.

Imaging and separation : Instrument separation and positioning are average and acceptable in the price range.

Conclusions :
For people searching a low budget mid centric earphone, this must be a try and the tuning is very good at this price.