The Korky toilet fill valve can be adjusted from 7 3/4 inches to 13 1/2 inches to fit most toilets. The key adjustment is the CL mark on the fill valve. This needs to be set 1 inch above the top of the pipe on the flush valve. The water level should be about 1/2 and inch below the top of the flush valve. If the water level needs to be adjusted, just twist and lock the body of the fill valve. Check out more home improvement tips in our e-books https://www.amazon.com/gp/product/B0B2KW1FQ9?notRedirectToSDP=1&.