Viega 20748 ProPress coupling No stop Smart Connect technology Copper, 3'' x 3''

No stop means the coupling has no internal ridge separating the two sockets, so a tube can slide all the way through. That is what you want on a repair: cut out the damaged section, slide the coupling over the existing line, position it, then press both ends. A stop coupling seats each tube end against a shoulder and is the choice for new runs where you want fixed insertion depth. The 20748 is a 3 inch by 3 inch copper coupling with P1 x P2 press ends.

Both ends are 3 inch press, listed as a 3 inch x 3 inch copper coupling with P1 x P2 connections. It joins 3 inch copper tube to 3 inch copper tube, straight through, no size change. For a transition to another size you need a reducing coupling instead.

That is exactly what the no stop version is for. Because nothing inside blocks the tube, you slide the 20748 along the existing 3 inch copper, center it over the gap you cut out, and press both halves in place. No soldering, no draining the line dry for a torch, and no need to free up an end of the pipe to slip a stop coupling on.

Smart Connect is a feature of the sealing element that leaks deliberately at an unpressed connection during pressure testing. On a 3 inch line with multiple joints, that turns a missed press into something you find at test rather than after the wall is closed. The 20748 carries it on both press ends.

The fitting itself measures 3.681 inches in height and length with a 4.921 inch width, but the clearance that decides the job is the swing room for the press ring and actuator, which is larger than the fitting. In tight chases or close to joists, check the ring footprint, not the coupling body.

Cut square, deburr inside and out, and wipe the tube clean so the seal is not riding over a burr or grit. Mark your insertion depth on both sides before you press, since a no stop coupling will not stop the tube for you, and an under-inserted end on a 3 inch line is a joint you will be cutting back out.