Sports Silicone Size Guide
SMALL/MEDIUM & MEDIUM LARGE BANDS INCLUDED WITH EACH PURCHASE
38/40 - Fits Apple Watches 38mm and 40mm (Fits Wrists 130mm - 180mm)
42/44 - Fits Apple Watches 42mm and 44mm (Fits Wrists 160mm - 200mm)
Please review underneath the face of your Apple Watch to determine the most appropriate size