2000BP KORKY CLASSIC PLUS FLAPP | The Korky Plus classic flapper is designed to stay open longer to fit old 5 and 7 gpf toilet models. The toilet flapper collar allows for attachment to brass flush valves and can be removed to fit plastic flush valves. The exclusive longest lasting red rubber resists chlorine, bacteria, city water treatment, hard water and well water. Made of flexible rubber for a tight seal and easy to install.