A grommet is a ring inserted into a hole through thin material, such as fabric

Fabric

A fabric is a textile material, short for "textile fabric".Fabric may also refer to:*Fabric , the spatial and geometric configuration of elements within a rock*Fabric , a nightclub in London, England...

. Grommets are generally flared or collared on each side to keep them in place, and are often made 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...

, 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...

, or rubber

Rubber

Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...

. They may be used to prevent tearing or abrasion of the pierced material, to cover sharp edges of the piercing, or both. A small grommet may also be called an eyelet, used on shoes for lacing purposes.

Grommets as reinforcement or crafting

Grommets are used to reinforce holes in leather

Leather

Leather is a durable and flexible material created via the tanning of putrescible animal rawhide and skin, primarily cattlehide. It can be produced through different manufacturing processes, ranging from cottage industry to heavy industry.-Forms:...

, clothing

Clothing

Clothing refers to any covering for the human body that is worn. The wearing of clothing is exclusively a human characteristic and is a feature of nearly all human societies...

, shoes, flags

FLAGS

The FLAGS pipeline is a natural gas pipeline in the North Sea which is used to transport liquids and associated gas from the following fields:* Cormorant A* North Cormorant* North West Hutton...

 and other fabric

Textile

A textile or cloth is a flexible woven material consisting of a network of natural or artificial fibres often referred to as thread or yarn. Yarn is produced by spinning raw fibres of wool, flax, cotton, or other material to produce long strands...

s. They can be made 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...

 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...

, and are easily used in common projects, requiring only the grommet itself, a grommet-setting tool

Tool

A tool is a device that can be used to produce an item or achieve a task, but that is not consumed in the process. Informally the word is also used to describe a procedure or process with a specific purpose. Tools that are used in particular fields or activities may have different designations such...

 (a metal rod with a convex tip usually sold with the grommets), and a hammer

Hammer

A hammer is a tool meant to deliver an impact to an object. The most common uses are for driving nails, fitting parts, forging metal and breaking up objects. Hammers are often designed for a specific purpose, and vary widely in their shape and structure. The usual features are a handle and a head,...

. Higher end grommet presses (as shown in the picture) exist as well, though generally a hammer and the grommet-setting tool is equally effective for small projects. Common uses include strengthening holes for boot and shoe laces, corset

Corset

A corset is a garment worn to hold and shape the torso into a desired shape for aesthetic or medical purposes...

s and other laced clothing, as well as curtains and other household items that require hanging from hooks. The grommet prevents the cord from tearing through the hole, thereby providing structural integrity. Small grommets are also called eyelets, especially when used in clothing or crafting. When using eyelets for crafting, they are generally used decoratively. When used in sailing and various other applications they are called cringle

Cringle

A cringle is an eye through which to pass a rope. In nautical settings, the word refers to a small hole anywhere along the edge or in the corner of a sail, rimmed with stranded cordage and worked into the boltrope. Typically it encloses a metal grommet for reinforcement and to reduce wear...

s.

Grommets used for cable protection

If metal or another hard material has a hole made in it, the hole may have sharp edges. Electrical

Electricity

Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...

 wire

Wire

A wire is a single, usually cylindrical, flexible strand or rod of metal. Wires are used to bear mechanical loads and to carry electricity and telecommunications signals. Wire is commonly formed by drawing the metal through a hole in a die or draw plate. Standard sizes are determined by various...

s, cord

Cord

Cord may refer to:* String or rope* Cord , a trimming made of multiple strands of yarn twisted together* The spinal cord* Cord Automobile, a former American car marque founded by Errett Lobban Cord* The cord , used to measure firewood...

, rope

Rope

A rope is a length of fibres, twisted or braided together to improve strength for pulling and connecting. It has tensile strength but is too flexible to provide compressive strength...

, lacings, or other soft vulnerable material passing through the hole can become abraded

Abrasion (mechanical)

Abrasion is the process of scuffing, scratching, wearing down, marring, or rubbing away. It can be intentionally imposed in a controlled process using an abrasive...

 or cut, or electrical insulation may break due to repeated flexing at the exit point. Rubber, plastic or plastic coated metal grommets are each used to avoid this. The smooth and sometimes soft inner surface of the grommet shields the wire from damage.

Grommets are generally used whenever wires pass through punched sheet metal

Sheet metal

Sheet metal is simply metal formed into thin and flat pieces. It is one of the fundamental forms used in metalworking, and can be cut and bent into a variety of different shapes. Countless everyday objects are constructed of the material...

 or plastic casings for this reason. Molded and continuous strip grommets, also known as edge grommets, are manufactured in a wide variety of sizes and lengths expressly for this purpose; they are usually a single piece which can be inserted by hand. Two-piece hard plastic devices are available which also grip the wire that passes through. This is called strain relief and is often used on power supply cords that attach to a piece of equipment, to prevent a tug on the wire from stressing the electrical connections inside the equipment. Sleeved grommets have a flexible extension (sleeve), usually tapered or moulded to flex increasingly towards the free end in order to prevent fracture of electrical insulation. Sometimes field workers may refer to grommets as grunyons.

Grommets used as wire managers

Cable management

Cable management refers to an important step during the installation of building services and the subsequent installation of equipment providing means to tidily secure electrical, data, and other cables...

 for furniture

A grommet can be used in furniture to protect wires, cables or cords for computer equipment or other electronic equipment in homes or offices. They are also used decoratively and can be bought in a large variety of sizes, colors and finishes.

The grommets usually consist of two pieces: A liner that goes into the hole of the furniture and a cap with a hole (often adjustable in size) for the cables to go through.

Surgical uses

In chronic cases of otitis media

Otitis media

Otitis media is inflammation of the middle ear, or a middle ear infection.It occurs in the area between the tympanic membrane and the inner ear, including a duct known as the eustachian tube. It is one of the two categories of ear inflammation that can underlie what is commonly called an earache,...

 with effusions present for months, surgery is sometimes performed to insert a grommet, called a "tympanostomy tube

Tympanostomy tube

A tympanostomy tube is a small tube inserted into the eardrum in order to keep the middle ear aerated for a prolonged period of time, and to prevent the accumulation of mucus in the middle ear. The operation to insert the tube involves a myringotomy...

" into the eardrum

Eardrum

The eardrum, or tympanic membrane, is a thin membrane that separates the external ear from the middle ear in humans and other tetrapods. Its function is to transmit sound from the air to the ossicles inside the middle ear. The malleus bone bridges the gap between the eardrum and the other ossicles...

 to allow air to pass through into the middle ear, and thus release any pressure buildup and help clear excess fluid within. This is also a correcting measure for a patulous Eustachian tube

Patulous Eustachian tube

Patulous Eustachian tube, also known as patent Eustachian tube, is the name of a rare physical disorder where the Eustachian tube, which is normally closed, instead stays intermittently open. When this occurs, the patient experiences autophony, the hearing of self-generated sounds...

(when air moves to and from the middle ear with each breath making the eardrum flap).