These sew-on hook-and-eye closures are metal; listings describe them as nickel-plated brass.
They are intended to be applied by hand sewing; the items are described as sewing fasteners used to hold fabric edges together.
Packages include two eye styles: round eyes for edges that meet directly, and straight eyes for overlapping edges.
They're commonly used on waistbands and apparel such as pants, skirts, dresses, lingerie, and costumes; some listings note specific sizing for skirts and pants waistbands.
Typical pack counts shown are 96 and 24, and one listing is labeled "Size 2."
Product descriptions state these closures are machine washable and dry cleanable.
Sew the hook to the waistband overlap and the eye to the underlap.
The listings show overall dimensions of 4.8 inches (L) by 2.9 inches (W).
Descriptions reference a nickel finish and specifically call out nickel-plated brass fasteners.
They are packaged in a reusable zipper storage bag.
One description calls them "extra sturdy," and the listings note a metal construction, indicating a sturdy metal design.