This is an excellent dummy holder for people who have children, like mine, who wake up in the night shouting for their dummy! My son quickly learned where the dummy was now attached and our quiet nights were restored.
It is attached via a clip that can be used on most sizes of clothing / cloth, and it has never come off.
The only downsides are i) that the clip has a rough edge to one side (a jagged side with 'teeth' that clips it shut), I has assumed this might cause problems, but it appears not to have (although it might for others); and ii) not all dummies do fit (you will need one without a 'ring' on it, but this isn't too much of a problem).