Heat-conducting hair rollers, a beauty accessory purchased at a convenience store

This is a heat-conducting hair roller, a beauty accessory I bought in a hurry at a convenience store last year.

I don't remember which convenience store I bought it for how much.

Regular rollers are made of plastic, but this one has metal inside, so it conducts heat when you dry it with warm air.

I like it because it retains heat for a long time, so the waves last a bit longer.