I use to think the 303 Fabric guard was the greatest protector and waterproofer for canvas there was until about 18 months ago. Did have to recoat about every 4-6 months. Could not get any 303 at Steinhatchee, Fla and had to use some Starbrite Waterproofer with TFE. Its about 40% less than 303 and the first coat lasted 12 months. I am impressed and will continue to use for the performance and price difference.