Match your Apple Watch to your outfit with casual Apple Watch straps. The watch straps are made of plastic, leather, and metal and all have a casual look. A plastic strap is resistant to water and sweat. That means you can keep it on when you exercise or shower. When you wear a leather strap for a longer time, the the leather often becomes more beautiful. With a metal strap, you look stylish and chic. When choosing a casual strap, make sure you choose the right size for your Apple Watch. 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.