Viega 25035 MegaPress coupling No stop Smart Connect technology Carbon steel, 3/4'' x 3/4''

Both ends are press. The 25035 is listed with a P1 x P2 connection, meaning a press socket on each side, sized 3/4 inch by 3/4 inch. There is nothing to thread, solder, or groove: you cut the pipe square, deburr, mark the insertion depth, and crimp each end with the press tool and the correct MegaPress jaw. If you need to land on a threaded valve or a piece of equipment, you have to pick up a press x FNPT or press x MNPT adapter separately, since this fitting won't do it.

A standard coupling has an internal ridge that stops the pipe halfway, so each end seats at a fixed depth. The 25035 has no stop, so the coupling slides freely along the pipe. That is what you want for a repair: cut out the damaged section, slide the 3/4 inch no-stop coupling fully onto one pipe end, bring the new piece up, slide the coupling back to center, and press both ends. Because there is no ridge to seat against, you must mark your insertion depth on both pipes with a marker before you press, or you can end up with too little engagement on one side. For a straight new-construction joint where both pipes are already fixed, a stop coupling is the easier part.

Yes, if the pipe is 3/4 inch nominal schedule pipe. The 25035 is sized 3/4 inch by 3/4 inch and presses onto the outside diameter of the pipe, so it goes over standard 3/4 inch black steel or carbon steel pipe regardless of whether the pipe was originally threaded. It does not care about the pipe's thread condition, only that the outside is round, clean, and free of deep scoring where the seal lands. Cut ends that are out of round or dented need to be trimmed back.

Smart Connect is a feature of the sealing element that lets an unpressed joint leak on purpose during pressure testing, so a connection you missed shows itself before the walls close up. It is a safeguard, not a substitute for pressing. Every joint on the 25035 still has to be crimped, and you still walk the line and pressure test.

The coupling body itself is 2.945 inches long and 1.496 inches across, so the fitting is compact. The real clearance question is the press tool: the jaw needs to come around the fitting square and rotate, so plan for the jaw envelope, not the 1.496 inch fitting diameter. In tight bays, an actuator with a swiveling head or a press ring and adapter jaw is what gets you into the space.