I bought the UP2 because I had the UP24 and it broke. I read all the reviews on Amazon and what resonated the most was that people lost the bracelet due to a loose clasp.  The bracelet is so light they didn’t even feel it. 

I made the safety clasp pictured below by cutting off the clasp part of an ID badge reel, trimmed it, and glued on a decorative stone. 

Now I don’t have to worry about losing it if the Jawbone clasp comes undone!