difference between fitbit 3 and fitbit 4

Fitbit Charge 4 vs Charge 3: 4 big apple watch 4 vs fitbit charge 3 Shop Fitbit Charge 2 vs Charge 3 vs Charge 4 FITBIT CHARGE 4 VS 3 // WHATS NEW Fitbit Charge 3 vs Fitbit Charge 4 Fitbit Charge 4 vs Charge 3. What's New Fitbit Charge 3 vs Fitbit Charge 4 differences between apple watch and Compare Mi Band 4 vs Honor Band 4 vs Fitbit Charge 3 vs Garmin Vivosmart 4 Fitbit Charge 4 vs Inspire HR: Reading Fitbit Charge 3 Vs Garmin Vivosmart 4 Fitbit Charge 4 vs Versa 2 Fitbit Charge 4 vs Versa 2: Make the Fitbit Charge 4 vs Charge 3: Is the Fitbit Charge 4 vs Charge 3 (2021 difference between fitbit 3 and fitbit 4