Best Fitbit Charge 4 (and Charge 3) bands: Leather, metal and sport straps
Shop Fitbit Charge 4™ & Charge 3™ Sport Accessory Bands
Faliogo Metal Replacement Strap Compatible with Fitbit Charge 3 Strap/Fitbit Charge 4 Strap, Adjustable Stainless Steel Wirst Band for Women Man, Small Large : Amazon.co.uk: Sports & Outdoors