Fitbit question

If you have are able to put it on before you buy (I'm assuming you are from your question), this is what Fitbit had me do to determine if mine was defective (when I used the Flex):

- put it on
- double tap it so it enters sleep/activity mode (it should vibrate and two lights will kind of dance back & forth on it)
- walk 100 steps ( you counting)
- sync the Fitbit and see how many it picked up

Mine really was defective. I did that test 3 times and all 3 it picked up 0 steps. You should expect to see somewhere right around 100 steps each time you do the test.