Update the look of your Flex 2 and personalise the colour with the Fitbit Accessory Bands. Whether you need the small or large band, this set is great for adding a pop of colour to your outfit, and because the bands are water resistant to 50 metres you can easily go swimming or get the band wet without worry. To get started, you simply have to remove the tracker from the back of your Fitbit Flex 2, and put it into the Accessory Band.