The Universal Flex PS-trap has 20 inches length, to replace rigid p-trap. Minimum water seal for Universal Flex P-trap is 2 inches and maximum water seal 4 inches. If you add 4 inches to the length of p-trap the water seal will be 4 inches. The Universal Flex PS-trap has 1.25 inches on sink and 1.50/1.25 inches on the wall’s draining. When you replace the regular p-trap on the plumbing line you don’t need to remove the pedestal sink, but you adjust the Flex P-trap by increase or decrease of the water seal. If you want to kip the water seal two inches (short p-trap) you need to cut the flexible tube to a specific length. The Universal Flex P-trap can be used some as Shampoo Bowl-drain hose when sink has the tailpiece.