Warner Tool Products has announced that the United States Patent and Trademark Office agrees and has issued Patent No. 6,668,751 relating to Warner's color-coded technology on ProGrip2 series of putty knives and scrapers. Every ProGrip2 handle has a molded insert that identifies the knife as stiff flex, flex or full flex. A red insert is used for stiff, blue for flex and yellow for full flex.

The company received its first patents more than 60 years ago for the single edge razor blade scraper.