Fitbit Zip Charge HR 101 Manual page 5

Charge HR 101
Wearing
Charge HR it is sweat, rain and splash proof.
However, the device is not swim proof or
showerproof. With any wearable device, it's
best for your skin if the band stays dry and
clean.
To track heart rate, your band should lay flat, a
finger's width above your wrist bone.
For better readings during exercise, wear the
band higher up on your wrist—about 2-3 finger
widths above your wrist bone.