thumb|right|Curtain grommets, used among others in [[shower curtains]]
A grommet is a ring or edge strip inserted into a hole through thin material, typically a sheet of textile fabric, sheet metal or composite of carbon fiber, wood or honeycomb. Grommets are generally flared or collared on each side to keep them in place, and are often made of metal, plastic, or rubber. They may be used to prevent tearing or abrasion of the pierced material or protection from abrasion of the insulation on the wire, cable, line being routed through the penetration, and to cover sharp edges of the piercing, or all of the above.
A small grommet may also be called an eyelet, used for example on shoes, tarps and sails for lacing purposes.
Grommets in electrical applications are referred to as "insulating bushings". Most common are molded rubber bushings that are inserted into hole diameters up to 2″ (51 mm). There are many hole configurations from standard round to assorted U-shapes. Larger penetrations that are irregular in shape as well as long straight edges are often fitted with extruded or stamped strips of continuous length, referred to as "grommet edging". This type of protective bushing is quite common in applications that range from telecom switches and data center cabinets to complex and dense wire/cable and even hydraulic tubing in aircraft, transportation vehicles and medical equipment.
As reinforcement or crafting
thumb|right|Metal eyelets and an eyelet setting toolthumb|[[Seaman's chest with grommets fashioned for use as handles]]
Grommets are typically used to reinforce holes in leather, cloth, shoes, canvas and other fabrics. It can alternatively be set with an electronic, pneumatic, or gas-powered machine. There are also dedicated grommet presses with punch and anvil, as shown in the picture, ranging from inexpensive to better-quality tools, which are somewhat faster to use.
Typical applications are footwear for boot and shoe laces, in laced clothing such as corsets, in flags for hoisting, and in curtains and other household items that require hanging from hooks, as when they are used in conjunction with tensioner rods for shower curtains. 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. Eyelets may be used purely decoratively for crafting. When used in sailing and various other applications, they are called cringles. Sometimes field workers refer to them as grunyons.
Maritime use
Traditionally, rope grommets have been widely used on sailing ships in a variety of ways. They have been utilized as chest handles or on row boats as a soft oar lock. They are a rope ring that is made by first disassembling the rope then re-weaving the strands to the desired size.
Use in electrical equipment
For cable protection
thumb|Cable grommets
Holes in metal or another hard material will often have sharp edges. Rubber, plastic or plastic coated metal grommets are used to avoid this. Tight fitting rubber grommets can also prevent the entry of dirt, air, water, etc.