This is strongly recommended for use on threaded pump connections.  The threads are machined, not molded, and they are graduated, insuring a tighter fit.

It greatly reduces the problems with drip leaks or air leaks at the intake and outlet of the pump.Use a pipe joint compound rather than silicone or teflon tape on the threads when screwing it into the pump.

Cut the nipple in half, use half on the intake side and half on the discharge side. Available in 2" or 1.5" sizes.