It's a really great earphone for $30 as a promotion. Even at the regular price of $150, it sounds good.
However, you must use a source device with good power. For example, if you use a stationary headphone amp, you can hear the sound of a proper Planamic type driver.
The fit is the best of any in-ear I've ever heard. It fits just right, not too small or too big, as if it was custom tailored to me.
In terms of class, the sound is similar to that of Mera or Ray solo, and although it is a little softer, the band is a little wider, and everything is well balanced.
JongsuChong3I agree. I purchased mine a while ago and in a drawer they sat until I tried them on a new 6W per channel amp and WOW, the sound is just a night/day difference. I had tried them on gaming DAC/Amp with poor results, so yeah, these really need a solid amp to shine and shine they do!