Sports Apple Watch straps are resistant to water and sweat. They're all made of plastic, which you can easily clean. Nylon watch straps for the Apple Watch breathe more than silicone or rubber straps. Choose a strap with a velcro closure if you want to put your Apple Watch on easily and quickly and adjust it to your wrist circumference. The Apple Watch 38, 40, 41, and 42mm straps fit on each of these sizes. The Apple Watch 44, 45, 46, and 49mm straps fit on each of those sizes.