This re-proofing product for all fabric & leather construction footwear is designed to enhance the water repellency of your boots which will maximise their breathability. When your boots become water logged on the outside they can no longer breathe making them feel damp & clammy on the inside & soggy & heavy to wear. This proofing liquid is easy to apply with the built in sponge & leaves a flexible water repellant treatment on the individual fibres of fabric & leather. This allows moisture vapour to pass through maintaining breathability & comfort. Nikwax waterproofing products are Water Based, non-aerosol, non-flammable, non-hazardous & environmentally friendly. They contain no harmful solvents or volatile organic compounds (VOCs), & are completely free of fluorocarbons (which have been shown to be persistent in the environment & have been associated with serious health issues).