This are the best streak preventers I've ever used. Cutting a piece of eisenglass works, but this are stiffer, hold up better, don't yellow, and maintain their shape. They're made out of a translucent 3M product and hold up well for years. I occasionally have to replace one every three or four years because they get a little brittle and break. Easy to install under the trim on your rubrail and have had absolutely no streaks on the hull since I started using them 10 years ago. Great product for the price.