I had to take a file to them to fit my Olympic bars. Also, dont expect them to offer the same noise isolation (or cancelation) as the much more expensive adult headsets. The ones I bought had a really adverse affect on the 580s sound and I suspect that all of the many resellers online are selling the same thing. I ordered a few models of cross-trainers, but like these the best. so I thought, ok, they?re dead. These are durable, cute and my grand daughter loves them! Can distort at higher volumes, but a nice unit overall. Someone has mentioned putting cardboard in them to hold better which is not a bad idea. I USE IT ALL DAY AND NO PAIN IN MY FOOT WILL BUY AGAIN . can also recharge case by setting it on my phone and enabling power share.