TRAN VAN DAT 4 Good: high brightness, easy to use, pretty design. This is a good product for night workout.No good: the band (or strap) is too short. So it is too tight for my upper arm. My muscle hurts after wearing it for half an hour.I tried wearing it around my wrist as a braceless but it is too loose.So it is too tight for upper arm and too loose for wrist.I have no choice but to wear it around my ankle.In conclusion, it is good for someone skinny or to wear around ankle.