Stampede String -- for hats without chin strap hooks : David Morgan

Coober Pedy Hat by Akubra

Chin Strap -- for hats with chin strap hooks : David Morgan

Chin Strap Hats at Village Hat Shop

David Morgan Stampede String Chin Strap Cowboy & Western Hats

The Territory by Akubra

Attaching a chinstrap to a hat equipped with chin strap hooks

Chin Strap Hats at Village Hat Shop

Paracord Hat Band - UK

This clever Chin Strap by Akubra is designed to break away if your hat is snagged while riding. The plastic releases pull apart with any excessive

Breakaway Chin Strap