I've owned several pairs of Sennheiser sports headphones, I've recommended them to anyone who will listen - each time I've bought a new pair I've paid a little more for a more premium product (15, 20 and then around 35 for these).
Unfortunately these weren't only the most expensive pair I bought but also the worst, the others filled your ears perfectly and had brilliant sound quality (by blocking out outside noise) and great fit - these are not great.
You get several attachments but I can't find a combination that fits, unlike the others these aren't trying 'in ear' they sit on your ear and the 'fin' attachments are supposed to keep them there - this doesn't work so well and I'm certain the person sat next to you can hear every word the same volume as you can.
As I'd destroyed the packaging I wrote to Sennheiser and told them I was unhappy with them and as a loyal customer would appreciate the opportunity to return them...they never responded and as such I am now hesitant about buying them again.
I think the pairing with Adidas has done more harm than good, they now seem to be more about looks than practicality which is a shame, they had a winning formula before!