Hooks and eyes are small metal fasteners that are often used in garment sewing. They are generally made of twisted wire and have two round loops on either side, with which to be sewn down. Hooks and eyes come in a wide range of sizes, from miniscule to immense, depending on their purpose.
They have a number of functions, most frequently in couture sewing. For example, a single hook and eye is often placed at the top of an invisible zipper to hold the neckline or waistband edges together. They are used to fasten collars and sleeve cuffs, custom belts, waist stays, and lingerie guards, or anywhere that a larger fastener would be inconvenient.