Fluid master's 400A universal toilet fill valve is the 1 best selling fill valve in the world. This is an anti-siphon design with an adjustable height from 9 inch to 14 inch. Code approved and proven to be trusted by toilet manufacturers worldwide. For best performance of your toilet, consider replacing the flapper along with the fill valve. Best fit with 3.5+ GPF toilets. To choose the right flapper, please view them at Fluidmaster toilet flappers.