Collar stays are shirt

Shirt

A shirt is a cloth garment for the upper body. Originally an undergarment worn exclusively by men, it has become, in American English, a catch-all term for almost any garment other than outerwear such as sweaters, coats, jackets, or undergarments such as bras, vests or base layers...

 accessories.

Collar stays are smooth, rigid strips of metal

Metal

A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

 (such as brass

Brass

Brass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...

, stainless steel

Stainless steel

In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....

, or sterling silver

Sterling silver

Sterling silver is an alloy of silver containing 92.5% by mass of silver and 7.5% by mass of other metals, usually copper. The sterling silver standard has a minimum millesimal fineness of 925....

), horn

Horn (anatomy)

A horn is a pointed projection of the skin on the head of various animals, consisting of a covering of horn surrounding a core of living bone. True horns are found mainly among the ruminant artiodactyls, in the families Antilocapridae and Bovidae...

, baleen

Baleen

Baleen or whalebone is a filter-feeder system inside the mouths of baleen whales. The baleen system works when a whale opens its mouth underwater and then water pours into the whale's mouth. The whale then pushes the water out, and animals such as krill are filtered by the baleen and remain as food...

, mother of pearl, or plastic

Plastic

A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

, rounded at one end and pointed at the other, inserted into specially made pockets on the underside of a man's shirt collar

Collar (clothing)

In clothing, a collar is the part of a shirt, dress, coat or blouse that fastens around or frames the neck. Among clothing construction professionals, a collar is differentiated from other necklines such as revers and lapels, by being made from a separate piece of fabric, rather than a folded or...

 to stabilize the collar’s points. The stays ensure that the collar lies flat against the collarbone, looking crisp and remaining in the correct place. Often shirts come with plastic stays which may eventually need to be replaced if they bend; metal replacements don't have this problem.

Collar stays can be found in haberdasher

Haberdasher

A haberdasher is a person who sells small articles for sewing, such as buttons, ribbons, zips, and other notions. In American English, haberdasher is another term for a men's outfitter. A haberdasher's shop or the items sold therein are called haberdashery.-Origin and use:The word appears in...

s, fabric- and sewing-supply stores and men's clothing stores.

Collar stays should be removed from shirts before dry cleaning or pressing, but then should always be put back by the dry cleaning company. Shirts that are press ironed with the collar stays are vulnerable to damage. Pressing with the collar stays in place results in a telltale impression of the collar stay in the fabric of the collar. Some shirts have stays which are sewn into the collar and aren't removable. This is the purpose of the small hole in the rounded end of the stay, the pointed end is often put in place against the corner of the collar and other end anchored by the small hole.