Find Your Size
When ordering a new Apple Watch band or bumper, it's important to know the case size to ensure everything fits your Apple Watch perfectly. Remember, sizing is based on your Apple Watch case size, not your wrist size.
One way to find your case size is by looking on the back of your Apple Watch device. However, the engraving is small and may be hard to read.
The easiest way to find your case size is by opening the Watch app on your iPhone. In the app, select "All Watches" in the top left corner. Then, you can easily verify your case size.
The easiest way to verify which Fitbit model you have is to look at the back or side of the device for the model number. It begins with FB and is followed by three digits. For example, Fitbit Sense has a model number FB512 and Fitbit Versa 3 has a model number FB511.
Here is a complete list of all major Fitbit devices and their model numbers:
|Fitbit||Model No.||Type||Release Date|
|Fitbit Flex||FB401||Tracker||May 2013|
|Fitbit Surge||FB501||Tracker||October 2014|
|Fitbit Charge||FB404||Tracker||November 2014|
|Fitbit Charge HR||FB405||Tracker||January 2015|
|Fitbit Blaze||FB502||Smartwatch||January 2016|
|Fitbit Alta||FB406||Tracker||February 2016|
|Fitbit Charge 2||FB407||Tracker||September 2016|
|Fitbit Flex 2||FB403||Tracker||October 2016|
|Fitbit Alta HR||FB408||Tracker||March 2017|
|Fitbit Ionic||FB503||Smartwatch||September 2017|
|Fitbit Versa||FB504||Smartwatch||April 2018|
|Fitbit Charge 3||FB409||Tracker||October 2018|
|Fitbit Inspire HR||FB413||Tracker||March 2019|
|Fitbit Inspire (NON-HR)||FB412||Tracker||March 2019|
|Fitbit Versa Lite||FB415||Smartwatch||March 2019|
|Fitbit Versa 2||FB507||Smartwatch||September 2019|
|Fitbit Charge 4||FB417||Tracker||March 2020|
|Fitbit Versa 3||FB511||Smartwatch||August 2020|
|Fitbit Sense||FB512||Smartwatch||September 2020|
|Fitbit Inspire 2||FB418||Tracker||September 2020|
|Fitbit Charge 5||FB421||Tracker||September 2021|