Premium Fabric Woven: Provide soft cushioning on the skin and allow moisture / sweat to escape; Soft breathable and lightweight. More comfortable than silicone and leather watch bands Double loops keep the extra strap length under control, more secure for wearing Washable Wristband: Easy to wash after getting dirty or wet. Use detergent if it stained by oil; use soap or toothpaste when stained by sweat or others; toothbrush will be a helpful tool Series SE, Series 7, Series 6,Series 5 4 3 2 1