I have 3 big complaints against this peice 1. Although the audio quality is decent the base is just not there. The headphones which came with my phone sounded much better. If you pay 3.5k for a pair of headphones you want it sounding better than a stock item which came with your phone. 2. There seems to be some loose connection between the volume control and the headphones. If you slot it too tight there is no sound flowing through to the headphones. Also when you use it with the volume control, for running, the volume control unplugs too easily because of the shaking. Since Sennheiser says its a sports headphones, the plug should slot into the volume control tight enough as any sporting activity such as running the wires are prone to a lot of shaking. Now I do away with the volume control on my runs. I just use only the headphones. 3. One of the main reason I bought this headphones is because of the flexible material which goes around the ear. This is supposed to keep the phones in your ear during any intense work out. Well this is only on paper as it constantly kept falling off on my run today morning. I guess the only way of preventing it from falling off is spending a good 5 minutes just to put the headphones on and wrapping it nicely around the ears. 5 minutes just to put it on.. Come on!!! I would rather finish a km of my run in that time..