These are a splint or brace that you wear at night that are supposed to correct bunions. There is some debate if they do correct them or not, but the research shows that they can improve the angle of the big toe by a few degrees after a month of use.
Most Useful Resources:
Do bunion correctors work?
Do Bunion Correctors Work?
Do the “Bunion Correctors” actually work?
The Bunion Correctors
Bunion corrector gullibility
The bunion correctors – do they work?