I bought this mp3 player for use at the pool doing laps The ear should be fully seated in the ear pavilions to avoid that water enters and degrades the sound In use it is a pleasure to swim in music, one is transported It can be used under water but in this case it seeps a little and makes the cavernous sound without being really unpleasant: I thus made a pool length snorkeling was pretty magical Conclusion very satisfied with my purchase, good sound quality and really tight I take off a star for the perfectible sealing headphones at ear level (a listener custom would be perfect but it would not be the same price!) And there is no navigation in files (sequential read All pieces that do not account for records or they are stored)