These were not as popular as the cotton face covers and buffs between January and March/April of 2020, but as people "up" their PPE game we are seeing more and more bulk sales of these acetate film PPE masks. As you can see in the model photo below, a lot of people double up with the traditional mask and the shield over everything, because it also offers protection to the eyes.
Think of your face as a walking salad bar, and the acetate shield as a sneeze guard.
Here's some official info:
The Face Shield is ideal for maximizing personal protection. It is made of clear acetate film with white paper trim. The large design covers the forehead to below the neck. It can function with or without a mouth mask and protects against airborne moisture droplets. Headband size is adjustable from 20.5" x to 26.125" and it is disposable for one-time use. Some assembly is required and the shield is recyclable and compostable. Sold blank. Prepayment only and exempt from VIR. ACH, wire transfer or CC subject to 3% surcharge.