Nikwax Down Proof Waterproofing treatment for down or feather filled clothing, sleeping bags, and comforters/duvets Helps revive insulating qualities while adding water repellency to the shell fabric exterior and down interior of your gear Easy wash-in application; Machine wash safe Safe for use on jackets, gear and bedding with down-fill, down blends, or water resistent down (such as Nikwax Hydrophobic Down) Water based, biodegradeable, and contains no PFCs or VOCs