Specification: Name Face Mask Replacement Pad Meterial Non woven fabric Quantity 30pcs Please Know:- It is recommended to replace it once every 2 hours, & the single piece should not exceed 4 hours.- It is recommended to take 5 tablets out of the house every day & change them every 2 hours between 9 & 18 o'clock. On the way to & from work, it is recommended to replace the mask directly if you are travelling on vehicles with high crowd density.- Use disposable masks during working hours, one can hold 3-5 masks; On the way to & from work, it is suggested to change directly. After arriving at the destination, one mask can meet the demand of working time in one day by changing mask pads. Package included:30PCS X Face Mask Filter Pad (Face mask is not included)