Size Chart 38mm & 40mm Size: 38mm/40mm-S/M means size Small: Suitable for 5.1"-7.1" (130mm-180mm) wrist; 38mm/40mm-M/L means size Large: Suitable for 5.9"-7.9" (150mm-200mm) wrist; 42mm & 44mm Size: 42mm/44mm-S/M means size Small: Suitable for 5.5"-7.5" (140mm-190mm) wrist; 42mm/44mm-M/L means size Large: Suitable for 6.3"-8.3" (160mm-210mm) wrist. Product Description Soft Silicone Material: Soft and Breathable Silicone material keeps your wrist comfortable when wearing and sleeping, You don't have to worry about any allergic reactions Multi-color: Rich colors and fashion style to meet your diverse needs. Personalize your Apple watch and highlight your unique taste, choose the color you like today based on your own mood. Safety Performance The apple watch band comes with watch lugs on both ends, which locks onto apple watch interface precisely and securely and will let the apple watch bands stay in place and will not be fall off.