Push Fit Coupler is a quick-connect pipe fitting used to join two pipes without welding, threading, or using special tools. It is widely used in plumbing, HDPE ducting, RO systems, and cable protection because of its fast installation and leak-proof performance. A push fit coupler works on a push-to-connect mechanism. You simply push the pipe into the fitting, and the internal locking teeth and rubber O-ring create a tight, leak-proof seal.