A face shield should:

Question

To be effective, a face shield must be free of scratches; be resistant to penetration; allow clear views to both sides; fasten securely; permit air to pass through; and permit enough room for eyeglasses or sunglasses, if needed.

Accepted Answer

Allow a clear view to both sides.

Answer

Prevent air from passing through it.

Answer

Be tight enough to prevent glasses from fitting underneath it.

Answer

Should not fasten too tightly.