I do not know if this be a bad design or I just have my bad luck get a defect one . when I walk around with this stuff on , I can hear a very disturbing noise . later I find out the earphone actually deliver and amplify the friction noise between its cord and the zipper on my jacket to my ear ! you can avoid this problem by be static -lrb- people alive will not always be static -rrb- , or by wear soft material clothing with no zipper . other pro and con . pro : decent sound quality build in volumn contol con : ugly look except the sennheiser brand on it uncomfortable earbud -lrb- too large -rrb-