The Well Casing has a 4" long straight end (not corrugated) on each end of pipe. The one end is the same diameter as outside of pipe and the other end is a smaller diameter. Therefore the small end fits into the larger end and the pipe can only be joined at these straight ends. This bell and splicket joint is fastened together by using eight self-tapping plated #10 screws ¼" diameter by 2" long. An epoxy sealant (Sika) can be used to obtain a water tight seal.