The design of these face shield uses plastic headbands that are regulatory worn of top of the head to hold hair away from the eyes or face. The reason for this switch was due to the time intensive process of 3D printing that did not allow to for a quick manufacturing turn around.

Time comparison:

3D printing one headband = 1.5 hours
Riveting one headband = 5 minutes

By saving this much time we can produce more face shields and therefore reach more people in need of protective equipment.