Nice for wearing around your ankle.
My Fitbit Alta HR fits perfectly in the little pocket and seems secure.  It is also comfortable.  It does exactly what it claims and is well made.  It counts my steps by does not track my heart rate, which I assumed it wouldn't since it the unit is within fabric. For that, I had better luck with the band extenders.  That being said, this is definitely a good, comfortable, option.  I wouldn't hesitate to buy it.
Rating: 5 stars