"Restart" is found on your Fusion Lite, under apps > settings , and will simply power your Lite off and back on.
"Factory Reset" is found on your Fusion Lite, under apps > settings , and will delete all the recorded data on your Lite (data already synced to your phone will remain on our servers linked to your account) and restore it to factory settings. Your Lite will display a 4 digit pairing code (and/or "striiv.com/start and battery %) as it did coming out of the retail box. After doing a Factory Reset, you'll have to re-pair your Fusion Lite to your phone.
To do a "Pin Reset," place your Fusion Lite back into its charging cradle with the cradle plugged into a power source. Flip it over and use the end of a paperclip to hold down the tiny button marked "Reset" on the back of the charging cradle. This is essentially another method to restart your device.