High-quality material Made of durable neoprene for a long-lasting, comfortable fit in water. Integrated design Back-of-head double-layer hair band protects hair from the mask strap and helps secure the diving mask to prevent slipping during dives. Suitable for multiple sizes Measures 18.5 x 8 cm (7.28 x 3.15 in); fits most head sizes for adults and children. Wide range of applications Ideal for snorkelling, diving, swimming and other water activities; an essential piece of water sports equipment. Use scenarios - Snorkelling with long hair to prevent hair from being pulled or tangled by the strap. - Diving or scuba to maintain mask stability and prevent slip. - Swimming lessons or family swimming to keep the mask secure and comfortable for kids and adults.