Nikwax Cotton Proof Fabric Water Repellent (33.8 ounces) Adds water repellency to cotton and polycotton and maintains breathability Prolongs the life of gear and optimizes performance in wet weather Easy to apply - can be used in a washing machine, no tumble drying required Inhibits rotting of canvas caused by dampness Water Based, biodegradable, non flammable, non hazardous. Does not contain fluorocarbons