COMFORTABLY —— The soft and wider band fits the head or neck and minimizes the pressure, relieves pain on ears caused by wearing your mask and allows you to wear the mask comfortably for a extended time ARBITRARY ADJUSTMENT —— The limit of an unlimited fixed number of adjustment points provides perfect custom fit, It can ensure that the mask fits the face with any degree of tightness COMPENDIOUS DESIGN —— There are no extra buckles or complicated pull loops,just lightly stick to complete the wearing, convenient and fast, children and the elderly can be used without obstacles. REUSABLE —— It can be washed by hand repeatedly to remove sweat or dust and keep your extension belt clean.Pure nylon material, soft and durable.