TR218 replacement stem assembly for tractor tire and construction tubes. Includes base, plastic rim nut, and core housing with cap. THESE ARE FOR PROFESSIONAL INSTALLATION ONLY. This requires knowledge of chemical cold vulcanization tube repair to install. You will need a tire/tube buffer and professional grade fresh cold vulcanizing fluid (not the can you opened and have had on the shelf a year). See the pictures showing how it is done. The old stem assembly is cut from the tube. The area is then buffed larger than the replacement stem base. Cold vulcanizing fluid is applied to the tube and allowed to dry completely. The replacement stem base is applied over the center of the hole, we use long core tool to center it and drop it on the hole. The stem is then stitched down.