Sports Silicone Size Guide
SMALL/MEDIUM & MEDIUM LARGE BANDS INCLUDED WITH EACH PURCHASE
38/40/41 - Fits Apple Watches 38mm, 40mm and 41mm (Fits Wrists 130mm - 180mm)
42/44/45/49 - Fits Apple Watches 42mm, 44mm, 45mm and 49mm (Fits Wrists 160mm - 200mm)
Please review underneath the face of your Apple Watch to determine the most appropriate size