The easy to use, safe, high performance, wash in waterproofing for cotton, polycotton and canvas. Adds Durable Water Repellency; reducing weight gain and maintaining the breathability of cotton, polycotton and canvas, in wet weather.
Nikwax says about the Cottonproof
For waterproofing cotton. Easy to use wash-in waterproofing for all cotton, polycotton, canvas clothing and equipment. Adds water repellency, revives breathability and reduces water absorbency. Enhances the performance of your gear, keeping you warmer and drier. Recommended for all cotton and polycotton clothing and gear.