Compatible Models: Replacement band is compatible with 4.0 (Note: U-shaped bracket is not included). Easy to Replace: Adjust the length of the band to suit your size, then remove the old band, replace the new band, and secure it with the original U-shaped bracket. Size fits all arm biceps/ankles, forearms or upper arms from 7.5 to 16.5 inches, suitable for men and women High Quality Material: This arm/ankle band is made of high quality nylon material, breathable, elastic, adjustable, comfortable, etc., suitable for sports activities or exercise Easy Care: Washable, durable, wear-resistant, no pilling, no fading After-sales Service- If you have any questions, please feel free to contact us, we will reply you in time