You can get the pressure nipples at most any hobby shop or from places like tower. You just drill a hole in the muffler and screw it in. Some are self tapping and some you have to cut the threads yourself. Sometimes the muffler comes with the nipple in the box but not always. When I used slimline mufflers I had to keep the nipples on hand and install them myself so I started stocking them in my building box.