The Fluidmaster 400A Universal Fill Valve is the #1 best selling fill valve in the world! This is an anti-siphon design with an adjustable height from 9? to 14?. Replaces ballcocks universal fill valve. Easy to install. Fills quickly. Universal fit for 1 and 2 piece toilets. Corrosion resistant. Anti-siphon operation, code approved. Won't contaminate fresh water supply.