A grommet cap is the best feature of a desk grommet. Most of the grommets come with a central opening. Usually, there are no lids or grommet caps to cover the hole. Wires and cables pass through grommets and plug in a socket. So, most of the time, we do not need a cap. But, desks are different. You need to close the hole sometimes to make it presentable or keep things safe. It becomes necessary if you are using the table to control devices and connecting to the network. The traditional shape of a grommet opening resembles the letter U. But, it can be rectangular or oval. Most of the grommet caps come in U shape, too, to fit the space. Some caps cover only half of the opening and some opens out wholly. There are several materials available for making a grommet. Plastic, rubber, and metal are the most popular materials for the grommet. But, if you are an environmentalist, then you may leave the plastic out of your list. 

Choosing the best desk grommet is not a tough job. But, it would be best if you took some sectors before choosing the grommet cap to fit in your purpose. For example, the type of flap. Adjustable caps come out entirely and give you reasonable access while you use them. Then comes the slide top grommets. Sliding grommet caps are space-saving and most convenient to use in office settings. Also, these are helpful where you need to pile up files on the table. Brush caps give extra support and security to your cables while handling them gently. Hinge caps are the newest edition of grommets. 

Hinge grommet caps open half or complete parts depending on the Angulation of the joint. Nowadays, you can use these for decorative purpose too.