Marketing InformationFluidmaster® recommends Fluidmaster® 400A universal toilet fill valve is the No. 1 best selling fill valve in the world. A universal design, with an adjustable height from 9 to 14 in to fit most toilets. The 400A offers quick refill rates and replaces ballcocks and other toilet fill valves. A trusted and proven toilet fill valve, the 400A is built to last from corrosion-resistant materials for a long lifespan. This code approved, anti-siphon design, won't contaminate the fresh water supply. Some toilet models not supported Glacier Bay® or Niagara® flapperless toilets, one-piece toilets. Does not replace side entry valves. Fluidmaster® late Founder invented the fill valve technology in 1958.