PACK of 40 Facial Dustproof Masks WE INSIST 3-PLY MASK - Usually the masks are three-ply (three layers). This three-ply material is made up from a melt-blown material placed between non-woven fabric. The melt-blown material acts as the filter that well stops Dust/Saliva from entering or exiting the masks. SOFT BUT RELIABLE - Soft and comfortable ear hook markss, not easy to drop, no need to adjust it when you work. A flexible Nose bar is adopted at the bridge of nose; The four sides of the marks join flatly and tightly to the face; Hence, it avoids unfiltered air directly entering into the masks and thus make breathe safely. Disposable, lightweight, comfortable, odorless, fiberglass free, Stay healthy and safe when at work or out and about by wearing one of our hypoallergenic dust masks. THREE MASKS A DAY - masks contain filters that prevent spray and pollutants from being spread. For hygiene reasons, use disposable markss and replace them when they get moist. markss can only be worn for a maximum of four hours and it is best to change them regularly so they can remain effective. THE RIGHT WAY TO WAER A MASK - The BLUE side of the marks is usually the front and should face away from you, while the white side touches your face. Please note: When wearing masks, do not excessively pull the strings at both sides or they will break.