User's Manual

• Make sure the watch is in contact with your skin.

• Don't wear your watch too tight; a tight band restricts blood flow, potentially

affecting the heart-rate signal. However, the watch should be slightly tighter

(snug but not constricting) during exercise than during all-day wear.

• With high-intensity interval training or other activities where your wrist is

moving vigorously and non-rhythmically, the movement may limit the

sensor's ability to provide a heart-rate reading. If your watch doesn't show a

heart-rate reading, try relaxing your wrist and staying still briefly (about 10

seconds). You should see a heart-rate reading.

Handedness

For greater accuracy, you must specify whether you wear FB415 on your dominant

or non-dominant hand. Your dominant hand is the one you use for writing and

eating. By default, the Wrist setting is set to non-dominant. If you wear FB415 on

your dominant hand, change the Wrist setting in the Fitbit app.

Change the wristband

FB415 comes with a small wristband attached and an additional large bottom

band in the box. Both the top and bottom bands can be swapped with accessory

bands, sold separately. For wristband measurements, see Wristband size on page

44.

Remove a wristband

To remove the wristband:

1. Turn FB415 over and find the quick-release lever—there's one on each end

where the band meets the frame.

2. To release the band, push the quick-release lever inward.