The sound from these earbuds is phenomenal, especially for the price. Great clarity, nice strong bass. My preferred headphones are Porta Pros, but for the city I require earbuds that block out ambient noise. These do the trick, providing excellent output when I'm on the subway or walking around the city. My prior earbuds were a similarly-priced pair from Sony, and this set demolishes those.
My only qualm is that the cord is very thin and coated in a tacky (in the sense of "sticky") rubber that seems designed to make the cord bunch and tangle as much as possible. I would have preferred the cord to be coated in cloth or to be somewhat thicker.
The buttons on the in-line control were also a bit stiff at first, but they are becoming clicky-er the more I use them.
Review by Ian /
(Posted on 3/24/2016)
Very good in performance
Overall
Body is good but should improve more quality in wire. Excellent bass punch, equivalent of most famous brands, nothing less.
Pros: Good balance of low and high as well as vocal.
Cons: Negligible
Review by Ravi /
(Posted on 10/11/2013)
Terrific
Overall
At the price you can typically find these they are a great value. The noise isolation works well, the frequency response is good, and the bass response is excellent. I'm very happy with these. Given that I tend to lose earbuds a couple of times a year, replacing these isn't so hard to take. They (and the similar KEB30's) are much quieter than Apple's standard-issue buds, so if you're used to blasting the volume with Apple's buds, you'll be hard pressed to match the volume level with these.
Pros: Comfortable. Crisp sound. Good frequency response.
Cons: (Relatively) low sensitivity.
Review by Interocitor /
(Posted on 2/7/2013)
My first Koss Earbuds for Mobile Phone
Overall
I own several Koss headphones including my classic Pro4AAA and ProDJ100 and Porta Pro and XT Pro. Tried to get some input regarding these babies from the Facebook page but no one responded. Well listening to Gordon Goodwin while writing this review. Loving them!
Pros: Great sound, solid build, nice design.. of course what you expect from Koss
Cons: No android support ... hopefully in the future
Review by VideoGuyLA /
(Posted on 2/5/2013)
15 - 20,000 Hz 
16 Ohms 
100 dB SPL 
Straight, Single Entry, 4ft with 3.5 mm plug 
Limited Lifetime Warranty 
John C. Koss, Founder