I needed to replace the battery for my Zen Xtra, and this looked like it would work. Like another review said, it's a bit too small. I had to cut a guitar pick into a sliver and slide it in between the battery and the body of the MP3 player to keep the battery from losing contact.It works fine, holds about a 6-8 hour charge. I wish it was big enough, I hate modifying new products out of the box like this. But, it works alright, I'm happy.