The Centrostyle Adjustable Retainer Bands, blue color, are a sporty silicone cord with elastic holders that fit on the back of the arm. They feature a clip for length adjustment, allowing a tight or loose fit on the head. Suitable for thin and medium thickness arms. They are very soft and flexible, made from hypoallergenic materials. Ideal for use in sports, at the sea, and in the mountains. CentroStyle comes from Italy and manufactures sunglasses and optical glasses with very lightweight materials, weighing 12 grams, for all ages.