its a tube and you tighten a nylon tube around your head. Then you pull the tube. There is three tubes all together. When you pull the tube you strecth and then you locked it with a pin. That stuff strecth longer than when you use your hand. Right know I'm stretching it to like 9 in fluccid. You move up like 2 cm a week depends on how much you use it. If you get a bonner in the tube your head looks small and your uretha will get bigger. If you put it more than 3 hours long your head hurts like hell.
One time when I went to church and have it on I wanted to take it off. Around your head where you put your nylon string will turn blue or purple. I got mine for $46 total the website cost like 90.