Face shields are items to help prevent infection from the Coronovirus. They physically block liquid from reaching your face and eyes.
They prevent you from touching your face or rubbing your eyes.
There are disposable face shields that are meant to be used for the day then discarded. They can be cleaned and sterilized but they are designed to be used a few times and discarded. There are reusable face shields that can be sterilized, cleaned and re-used over and over.