I made an impression of the Tennmak Pro in the big Chinese IEM thread if you want to quote me and what I'm about type isn't detailed enough.
Tennmak Pro Dual Driver IEM ($22):
Sound: Initially, the bass was decent, and didn't go very deep but was fast. The midrange was a little warm, but still accurate. The treble was smooth, but detailed enough, and never simblant. Now, at about 100 hours, the sub-bass has improved vastly, midrange the same, treble is maybe a little bit crisper, but that is more likely my ears adapting to the IEMs. Soundstage has always been above average, vocals seem to be far in front of me or close depending on mixing, placement of instruments is top notch.
Aesthetics/durability: I love the aesthetics of them, the plastic is smooth, durable, and transparent. I've been rough with them, I carry them around in my pocket and I'm quite clumsy and walk into tables/cars/chairs all the time and they've faired pretty well considering. The Tennmak logos on the backs of them have rubbed partially off and one back fell off one time, but I just Gorilla glued it back on. They're still working and me being me, that's fantastic. I even attempted to mod them by drilling two holes into the backs of them. I'm honestly not sure if the mod did anything, but they're so working great and the plastic didn't crack from my drilling so...
For $22 I give them 2 thumbs up