These filters are washed three times with deionized water, dried at 105°C, then furnace treated at 550°C to remove any volatile components. They are then weighed to 0.0001g. Each filter is in an individual aluminum pan with the filter weight printed on a Mylar® label affixed to the pan. Filter weight and ID number are also printed in code 128 barcode format. Caution, Mylar® label will only withstand 180°C.