Manufactured from solid sheets of 100% blown polypropylene. It absorbs oil/fuel in the bilge so that remaining water can be pumped overboard. Absorbs 2 quarts of hydrocarbon. The "safety skin", a tough universal fabric skin, absorbs small amounts of water making the bilge absorbent fire resistant without interfering with its oil absorbency. This skin assures that the absorbent material will not get into the bilge and possibly foul moving parts. Great way to avoid fines from pumping oil overboard. Help keep our waterways clean. Convenient tie downs keep booms in place.