TPU straps are four different sizes, rubber straps for Apple Watch Series 7 6 5/4/3/2/1, it has 10 colors, each color will have a different style performance with the watch. Main Functions: 1. The strap is made of thermoplastic polyurethane elastomer rubber, referred to as TPU, which is moderately soft and comfortable to wear. 2. More durable than ordinary silicone, high wear resistance, low temperature performance, more resistant to dirt 3. Solid color, simple lifestyle. 3. The size can be adjusted according to individual wrist. 4. Accept OEM/ODM service.