Our adult neck gaiters feature a super stretchy fabric that accommodates most head sizes. It is breathable, lightweight and feel comfortable. Many ways to wear it. Good for outdoor activities. In addition to these, you can put a anti-dust filter into the filter pocket. Pls noted the price is not included the filter.The children size 11" L x 8 7/10" W is also available. This adult size is 19 7/10" L x 9 4/5" W.