Reusable Waterproof Shower Cap. Size: Outer diameter 10.6 inches/27 cm, the inner diameter: 4.3 inches/11 cm, suitable for most head circumferences and the longest natural thick hair. Double-Layer Waterproof design: The cap contains a water-repellent polyester outer layer and a peva inner layer, which is skin-friendly, soft, waterproof, and light-weight and portable. Makes A Great Gift: Women, men, teens, and kids will love this adorable and thoughtful beauty gift. Washing Instructions: Clean Water Can Be Washed, Can Be Reused.