Took a little time to work out the best fit for my ears so they wouldn't fall out while I swam, the "fin" piece helps keep them locked in and the "cone" piece helps keep water out of my ears! So I love that there was choices and mix and match options for the headphones.
The music sounds a little tinny/metalic when my head is out of the water, but once my head goes underwater it sounds better.
Love that I can add a whole bunch of music to the device, I don't use the bluetooth connection for anything.
Only improvements I can think of is the ability to pause and turn the sound up and down with a volume control by the earpiece (like a bose sound sport in-ear headphones), as I have to pull them out of my ears to explain to people at the pool what they are and say "yes they really work"! :)
Completely recommend these for people who want to listen to their music while they swim.