Tapered end for easy insertion Self-Sealing High quality 4" rubber plugs 4'' Rubber Plug Double Inlet 4" Rubber Plug is Suitable for internal & external use. They are designed to fit inside a 110mm pipe. They are supplied with a double closed conical-shaped inlet so that they may be cut to size on-site and will accept 32mm and/or 40mm Waste Pipe. They provide a means to protect and seal tubing used in various applications. Features Designed and developed for testing for leaks and for sealing off sections of pipelines. These pipe plugs are designed to insert into the end of the tubing to dead-end the flow. High-quality rubber plugs for your plumbing needs.