The Vietnamese PK-1 oro-nasal mask with Type 66 canister and goggles was the standard issue gas mask for the North Vietnamese Army. Imported from China, they offered protection against CS and CN tear gas. This example was made by ChiCom in 1967.
Similar masks in my collection: U.S. Navy Type 4 Comfo Mask
Goggles inside view
Goggles top view
Size stamp on goggles "1"
Size stamp on respirator "2"
Deteriorated rubber exhale valve
Respirator inside view