"Tatterwing" mechanism with light force, automatic locking The unique attachment method, the 3D headband features a "tatterfit" mechanism that wraps around the back of the head. Reflective stickers on front and back. Reflects light to let you know where you are. Rubber adjustment allows you to easily adjust the size of the headband Simply pull down the left and right tatta wings to make it folded. The flat folding style fits nicely into your desk for excellent storage. Approximately 35mm thick Whistle lets you know where you are. This product has passed national certification.