Solid heavy weight plastic.
Without sheet lifters when a binder is closed, the sheets jam in the hinge; it places unusual force on the hinge. When the binder is closing, the sheet lifters act as levers, moving the pages gently into the center of the rings. There is no need for pulling, and no stress on the pages.
Price is for 2 lifters (usually used one at the front and one at the back of the binder)
