Default Packaging: 50 pcs packed in each box - Colors: White;Blue - Period of Validity: 24 months - Executive Standard: GB/T 32610-2016 - Product Features: Size; 17.5x9.5cm - Weight: 2.5-3.3g - Materials: 1st Layer ; 25GSM non-woven 100% polypropylene 2nd Layer ; 25GSM Melt Blown Filter 3rd Layer ; 25GSM non-woven 100% polypropylene