Outer layers of tough-skinned, heavy weight SpunBond material resist abrasions and tears - can withstand rough handling and won't tear apart when pulled or positioned under equipment. MeltBlown inner layer draws and holds liquids from outer layers. Outer SpunBond layers are constructed of continuous strands of polypropylene fiber - interwoven to virtually eliminate fibers from becoming detached and contaminating equipment, tool or parts. Sold by the case.