... are constructed from compressed ,100 ppi(Z) open-cell polyurethane foam that is free from organic contaminants such as silicone ,amide ... . Laundered and packed under an ISO Class 4 Cleanroom, The foam exhibits low particulate and ionic content. It has excellent compatibility ... disk drive, LCD,PCB,SMT, IC, medical and biotech industry .Packing Info:500swabs/bag,50bags/ctn Other Swabs: Hard Disk Drive ...