Net Bags float on the water's surface to absorb oily spills and even surface sheen. Loose poly blend encased in a nylon mesh bag absorbs large amounts of petroleum-based liquid. Just toss Bags on a contained spill — heavy oils will adhere, while water is repelled, so Bags won’t become weighed down and capacity won't be wasted. This means you can leave them in place longer for maximum effectiveness. White color designates Oil-Only sorbency and makes it easy to identify when Bag is saturated.