Amazon.com: Pack 3 Silicone Bands for Fitbit Charge 4 / Fitbit Charge 3 / Charge 3 SE Replacement Wristbands for Women Men Small Large(Without Tracker) (Small: for 5.5"-7.1" Wrists, Black+Navy Blue+Wine Red) :
For Fitbit Charge 2 4 3 S Band Replacement Silicone Strap Soft Bands Small Large | eBay