This is a mash-up of Geekvader's excellent flip up face shield and the Prusa Pro shield found at https://www.prusaprinters.org/prints/32714-prusa-pro-face-shield.
This model is not designed with mass production in mind, although it might be possible. I am a vascular access RN and I occasionally work with COVID-19 patients. I don't need a "whatever I can get" shield. I need something that is comfortable and protective. My life may depend on it and my patients deserve for me to be at my best and not trying to work around a piece of shower curtain and a rubber band wrapped around my head.
This shield uses the larger, six-hole foil of the Prusa Pro. There is a template here: https://www.thingiverse.com/thing:4580747. This design is much more protective as it wraps around, rises up on the forehead, and provides full face protection. It also allows the use of thicker lens material that is held more securely. The lens used in the pictures is 0.03" PET. I wash it with soap and water
The forehead portion has been increased in height from the original to use 3/4" weatherstripping as a padding. It also includes buckles for using a 3/4" piece of elastic as an adjustable headband (I use 12-14" of elastic).