pro : flashy\/sporty design . lifetime warranty . sweaty resistant . con : earfin be a bad take on Sennheiser 's original `` twist-to-fit '' system . Soundquality be quite terrible . ------------------ First of , these headphone look good . the bright yellow and black color scheme be sexy . the build quality be quite good . very nice attention to little detail like the logo of `` Sennheiser '' on one side of the cable splitter and `` Adiddas '' on the other . the MX 680 come with many accessory , different size of the earfin and the rubber around the earbud . foam sock . and the thick and rugged carry case . I own the mx75 -lrb- 1st generation of Senn 's sport line -rrb- . I like the original `` twist to fit '' system much better , because instead of a sharp `` fin '' , they use round little wheel that roll much nicer against you ear and do not poke . the earfin be very soft and at time do not offer enough stiffness to keep the bud in my ear . when they do , they hurt my ear after just a few minute -lrb- and be distracting -rrb- the cable system be quite bad . you may ditch the volume control and just connect to a armband . the problem be , the cable be not long enough when I move my arm run . but if I use the extender with volume control , it be very heavy and add unwelcome tension to my ear . sennheiser do give you a clip that you can attach to the cable to keep it from dangle around . that be totally useless to I because I work out in t-shirt -lrb- and I do not know anyone who do not -rrb- , there be absolutely no place for it to clip on . SOUNDQUALITY - okay , these headphone sound tiny and thin . if you push they a bit into you ear they sound fantastic , but that be not feasible while lift weight , on a bike , or run . so , if you leave they on like normal , they sound no better than stock earbud that you get from buy any mp3 player . there be literally no base thump . you can hear the beat , but there be no impact . one way to look at this be that music sound extremely light , and will not become too involve or distract from you workout . but without any low and mid-low end to balance out the frequency , the high just be shrieky . it will sound like you brain be be scrape . other company offer headphone at much better value both above and below the price for the mx680 , with better comfort and better soundquality . there be no reason to pay so much money for these to replace you stock bud . except maybe for the look , but then you should look to other product of the sport range .