Face Coverings/Masks: Most Gaiters/buffs are made of material that allows for stretch. Knit materials are not adequate in reducing the transmission of airborne particles. Single layer gaiters/buffs are not effective in reducing transmission is particles. All face coverings must be at least two layers and fit to cover the nose and mouth appropriately. If a buff/gaiter has a suitable double layered weave material that cover the nose and mouth and extends under the chin with the stretch material around the back of the head, it will acceptable.