I had something like this years ago and loved it but could never find one again so I decided to create one. A pony tail belt. ;) At least that's the name of it thus far. It is a leather ponytail holder. More info below...

Boho chic leather hair accessory - Ponytail Belt

Adjustable for different thicknesses of hair. Designed with a non-slip feature that grips to most typical pony tail bands to prevent from slipping out of place.